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Upgrading nuclear and medical waste to dark matter detectors

A novel idea to probe specific classes of potential dark matter particles was recently suggested in this scientific article. It consisted in giving a second life to medical and nuclear waste as dark matter detectors. Before moving on with the details, let us come back a little bit on dark matter.

^{[image credits: @pab.ink]}

Detecting dark matter

Dark matter is probably one of the most searched for beasts in (astro)particle physics today, as it is indirectly evidenced by many cosmological observations. It however still escapes direct detection so that its true nature remains unknown.

This has led to the development of a plethora of theories featuring a particle playing the role of dark matter. In many of these theories, dark matter is expected to be observable on Earth in experiments relying on its very rare interactions with normal matter.

^{[image credits: Maxwell Hamilton (CC BY 2.0)]}

In practice, we wait for dark matter to hit one of the atomic nuclei of the detector material, which is then recorded to derive the properties of dark matter.

Dark matter particles must however be energetic enough to dump energy in the detector.

Dark matter can however be quite different so that these experiments would be significantly less sensitive. For instance, if dark matter is more strongly interacting, it could deposit all its energy in the atmosphere before reaching any ground-based detector (see e.g. here).

The newly introduced idea proposes to rely on an opposite mechanism. Instead of looking for dark matter depositing energy into normal matter, we could consider normal matter supplying energy to dark matter.

Recycling waste!

^{[image credits: Chandra @ NASA (public domain)]}

In order for nuclei to provide energy to dark matter, we need a detector made of atomic nuclei lying in an excited state.

When hit by a dark matter particle, such an excited atomic nucleus is de-excited, and release energy that is transferred to dark matter.

One could then directly observe the nuclear decay, or use standard detectors as dark matter has become more energetic.

However, where to find excited nuclei in large enough quantities to make a dark matter detector? The answer is simple. Nuclear and medical waste contains a large amount of long-lived nuclear isomers that are patiently waiting to be given a second life.

Dark matter is an option for their new life: these isomers could be packed close to an existing dark matter facility and then provide a mean to implement the new detection idea.

Could this work?

To illustrate the expectation of this new dark matter detection method, we can pick up a class of dark matter model and see how it is covered, as shown below.

^{[image credits: arXiv ]}

The two axes of the figure represent the two free parameters of the model. The grey areas are configurations excluded by current experiments. The three coloured curves consist in what the new method could do.

Anything above these curves is expected to be excluded by three isomers, i.e. ¹⁸⁰Ta (very abundant in nature), ¹⁷⁷Lu (remnant of cancer treatments) and ¹³⁷Ba (nuclear waste).

As can be seen from the figure, nuclear waste give access to many new configurations not reachable by standard techniques.

Take-home message

I discussed today a novel method for probing dark matter. It relies on the transfer of energy from an excited atomic nucleus (as available by giving a second life to nuclear and medical waste) to dark matter, making it easier to detect with standard techniques in cases where they would otherwise fail.

Whilst all of this lies at the theoretical level at the moment, it would be interesting to put it in place experimentally. But for that, we need to wait… at least a bit!

^{PS: This article has been formatted for the steemstem.io front-end. Please see here for a better reading.}

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Comments · 11

@shayan143(65)· 2533d
Like your all blog bro.
@shayan143(65)· 2533d
Nice one bro.
@steemstem(74)· 2556d

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@greenrun(66)· 2556d
This article particularly piqued my interest because of the likely application of nuclear waste as a detector. Have always being fascinated by the use of nuclear for energy production but somehow not too eager with how to manage the waste that will surely follow with running such an operation Let's see how this theories work out in practice. I'm keeping my fingers crossed while we wait
@agmoore2(64)· 2557d
I wrote a comment and lost it before I hit 'submit', so here I go again.

I'm not a fan of nuclear energy for at least 3 reasons:
1. Chernobyl/Fukushima syndrome (catastrophic failure)
2. Pollution of surrounding area (see: https://www.ncbi.nlm.nih.gov/books/NBK201991/)
3. And the half-life character of nuclear material that makes it relatively immortal
Feeding nuclear waste to dark matter takes care of objection #3. However, a nagging thought, which probably reflects my profound ignorance: Do we want energized dark matter? Doesn't dark matter gobble up everything in its path. Do we want to supercharge this entity?

Thank you for making theoretical physics accessible. There was a time when I would see the words 'dark matter' and hurry off because it had nothing to do with me. Now I feel much more comfortable with the 'matter' :)
@arcange(79)· 2558d
Congratulations @lemouth! Your post was mentioned in the Steem Hit Parade in the following category:
- Upvotes - Ranked 5 with 1569 upvotes
@abigail-dantes(67)· 2558d
Hi @lemouth,

Here I'm again reading about dark matter. Its elusive nature is what fascinates me most of all. So, learning about the steps that are being made towards its detection is rather intriguing for me now :)

I like how you presented this new method of "resurrecting" nuclear compounds through dark matter, as a means to detect it (?). It was straight-forward and straight to the point. It makes the read for someone like me quite exciting actually.

I also went through your comment section, which led me to another post of yours that, in fact, gave me an idea of the whole motivation behind the search for dark matter. This has made/will make my readings of materials about this topic much more meaningful :)

Thank you. Have a nice afternoon!
@inertia(75)· 2558d
Is it possible we have already had a direct detection dark matter at a certain sigma?
@mattgroening(59)· 2559d
And that just flies around at earth? I suppose it interacts with gravity, so it might get stuck here.
@ernestoluisgom1(13)· 2559d
dark matter detectors for what? mmmm well, it's a more efficient type of energy for use... much safer .. i mean, dark matter
@scienceblocks(68)· 2559d
This would be interesting of it would work. Even though I did not grasp the plot properly, I assume it takes care of interaction of nucleus that might happen with other stuff, say neutrinos and dark matter would have it's own characteristic signature. I guess that's what you meant?

On a slightly unrelated note this question came to my mind. Do we even know that dark matter flows through earth or earth passes through some region full of dark matter? How would we ensure that dark matter interaction would occur here on earth?