[Widdekind]

Consider a perfect (diamond) crystal lattice of carbon. Incident neutrinos would "alchemize" the C --> N. And, the N would induce defects, in the crystal lattice, which could be detected, e.g. w/ STEMs. Thus, could you not create a "solid state" neutrino detector, and simply expose it to some neutrino source; wait a while; then come back and "count the defects", divide by the detection time, and so have a neutrino detector ??

[Klaynos]

Widdekind, on 4 January 2012 - 10:51 AM, said:

Consider a perfect (diamond) crystal lattice of carbon. Incident neutrinos would "alchemize" the C --> N. And, the N would induce defects, in the crystal lattice, which could be detected, e.g. w/ STEMs. Thus, could you not create a "solid state" neutrino detector, and simply expose it to some neutrino source; wait a while; then come back and "count the defects", divide by the detection time, and so have a neutrino detector ??

I think your issue here would be the tiny interaction cross-section. You'd probably need a very big detector indeed to get any measurable signal.

[swansont]

Klaynos, on 4 January 2012 - 11:15 AM, said:

I think your issue here would be the tiny interaction cross-section. You'd probably need a very big detector indeed to get any measurable signal.

And you'd need to know how many defects are induced, or healed, by other means. Then there's the matter of how one actually counts the defects. AFAIK, STMs only look at surfaces.

[Klaynos]

swansont, on 4 January 2012 - 11:28 AM, said:

And you'd need to know how many defects are induced, or healed, by other means. Then there's the matter of how one actually counts the defects. AFAIK, STMs only look at surfaces.

Indeed, for some reason I read the op and assumed graphene... think I need to get out more...

[Widdekind]

What about using "layered sheets of graphene", oriented to "face" the neutrino source, and which could be separately STEM'd ? Or, a large graphene sheet, "rolled up", into a solid-and-dense cylinder, but which could be "unrolled" & STEM'd ?

Or, what about NMRI, for full interior scanning, of a 3D target ?

Cannot defect-less graphene sheets be manufactured ?

This post has been edited by Widdekind: 6 January 2012 - 09:49 AM

[Klaynos]

Widdekind, on 6 January 2012 - 09:47 AM, said:

What about using "layered sheets of graphene", oriented to "face" the neutrino source, and which could be separately STEM'd ?

It'd have to be MASSIVE!

Widdekind, on 6 January 2012 - 09:47 AM, said:

Or, what about NMRI, for full interior scanning, of a 3D target ?

Not sure on how easy the defects are to detect like this.

Widdekind, on 6 January 2012 - 09:47 AM, said:

Cannot defect-less graphene sheets be manufactured ?

HAHAHAHA! Nope, defects are par for the course currently. Fabrication is getting better but large scale defect free graphene is a long long way off. Defects are also created post manufacture. The group here has issues with oxygen and water doping of the surface causing defects. I'm aware of one form of spectroscopy measurement where your results change every time you run the scan due to continued modifications of the graphene. This also occurs when the sample is in a vacuum, surrounded by dry nitrogen, and at low temperature. It's quite a problem, fortunately we talked to this other group about their work before we started seriously investing time into the process.

[swansont]

Widdekind, on 6 January 2012 - 09:47 AM, said:

What about using "layered sheets of graphene", oriented to "face" the neutrino source, and which could be separately STEM'd ? Or, a large graphene sheet, "rolled up", into a solid-and-dense cylinder, but which could be "unrolled" & STEM'd ?

The mean free path in lead of low-energy neutrinos is measure in light-years.

[Widdekind]

swansont, on 6 January 2012 - 12:45 PM, said:

The mean free path in lead of low-energy neutrinos is measure in light-years.

"pencil lead" is denser than water, which is used in current neutrino detectors, yes? I don't know how to "catch" individual neutrinos, but current detectors passively rely, on "being notified", by the high-energy electron/positron, which emerges from nuclei, after they absorb neutrinos, i.e. "the neutrinos rip out a unit of charge, and emerge electrons".

Thus, such detectors require both a neutrino capture, and a subsequent observation. And, once they "notify" their environment, they "forget" and go back to the way they were. If you could construct a "solid state" neutrino detector, which "recorded" neutrino capture events, then you could make a "neutrino CCD", and take (long) exposures, to form "neutrino images". Some day, a "neutrino picture" may appear on APOD.

Perhaps you could gather angular resolution, by repeatedly re-orienting your "neutrino CCD plate". When the plate fully faced the source, maximum counts would occur. When the plate was perpendicular to the source, minimum counts would occur.

Also, I understand, that, via Weak Force interactions, quarks can change their "flavors", or "generations", e.g. . I also understand, that exiting anti-particles, can be "flipped to the other side of the equation", as incident particles, i.e. . Theoretically, perhaps "hyperonic matter", with exotic quarks, has a super-large neutrino capture cross-section ??? Perhaps stabilized "hyperon" states could be constructed, which would readily interact with neutrinos ???

[swansont]

Widdekind, on 7 January 2012 - 06:11 AM, said:

"pencil lead" is denser than water, which is used in current neutrino detectors, yes? I don't know how to "catch" individual neutrinos, but current detectors passively rely, on "being notified", by the high-energy electron/positron, which emerges from nuclei, after they absorb neutrinos, i.e. "the neutrinos rip out a unit of charge, and emerge electrons".

Yes. SNO, for example, uses 1000 tons of heavy water, and detected about 20 events per day. That's 1 event per hour for more than 10^31 target deuterium atoms. How many layers of carbon sheet would that be?

Widdekind, on 7 January 2012 - 06:11 AM, said:

Thus, such detectors require both a neutrino capture, and a subsequent observation. And, once they "notify" their environment, they "forget" and go back to the way they were. If you could construct a "solid state" neutrino detector, which "recorded" neutrino capture events, then you could make a "neutrino CCD", and take (long) exposures, to form "neutrino images". Some day, a "neutrino picture" may appear on APOD.

Perhaps you could gather angular resolution, by repeatedly re-orienting your "neutrino CCD plate". When the plate fully faced the source, maximum counts would occur. When the plate was perpendicular to the source, minimum counts would occur.

1000 tons. Rotated.

[Widdekind]

swansont, on 7 January 2012 - 01:21 PM, said:

Yes. SNO, for example, uses 1000 tons of heavy water, and detected about 20 events per day. That's 1 event per hour for more than 10^31 target deuterium atoms. How many layers of carbon sheet would that be?

roughly 1000 tons? that would be allot of graphene, to try to "actively read", so I see now why they use detectors that "notify" the experimenters. Why is it so hard to detect, when neutrinos "alchemize" matter, i.e. when nuclei are "driven around the Periodic Table" ? Or, why is it so hard to detect, the electrons / anti-electrons, which are "blown out" of the nuclei, by the "impacting" neutrinos ?

Quote

1000 tons. Rotated.

rotated within a (slightly larger) water tank, i.e. neutrally buoyant detector tank inside a larger secondary tank ?? You could use a rectangular tank, as a "super-large CCD pixel".

[insane_alien]

Widdekind, on 8 January 2012 - 12:16 PM, said:

Why is it so hard to detect, when neutrinos "alchemize" matter, i.e. when nuclei are "driven around the Periodic Table" ? Or, why is it so hard to detect, the electrons / anti-electrons, which are "blown out" of the nuclei, by the "impacting" neutrinos ?

because the signal is bloody tiny.

you can't do it my chemical means because the signal is only 1 part in 10^31.

positrons will annihilate quickly and the gamma rays are likely to be absorbed before they hit a detector.

It's so hard because there is almost no signal and there are plenty of interferences, such as radioactivity of your detector, radioactivity of your surroundings, cosmic rays etc.

This is why they build the detectors so far underground, and try their damndest to block all sources of radiation.

[swansont]

Widdekind, on 8 January 2012 - 12:16 PM, said:

roughly 1000 tons? that would be allot of graphene, to try to "actively read", so I see now why they use detectors that "notify" the experimenters. Why is it so hard to detect, when neutrinos "alchemize" matter, i.e. when nuclei are "driven around the Periodic Table" ? Or, why is it so hard to detect, the electrons / anti-electrons, which are "blown out" of the nuclei, by the "impacting" neutrinos ?

Yes, 1000 tons.

The detection of the event itself is not inherently hard, it's that they are rare and there is significant background. The cross-section for the weak interaction is very, very small. It is surprising to me that someone who has acquired such knowledge about nuclear interactions could somehow miss such a basic piece of the puzzle.