Construction begins on one of the world's most sensitive dark matter experiments

Construction begins on one of the world's most sensitive dark matter experiments
The future SuperCDMS SNOLAB experiment will hunt for weakly interacting massive particles (WIMPs), hypothetical components of dark matter. If a WIMP (white trace) strikes an atom inside the experiment's detector crystals (gray), it will cause the crystal lattice to vibrate (blue). The collision will also send electrons (red) through the crystal that enhance the vibrations. Credit: Greg Stewart/SLAC National Accelerator Laboratory

The U.S. Department of Energy has approved funding and start of construction for the SuperCDMS SNOLAB experiment, which will begin operations in the early 2020s to hunt for hypothetical dark matter particles called weakly interacting massive particles, or WIMPs. The experiment will be at least 50 times more sensitive than its predecessor, exploring WIMP properties that can't be probed by other experiments and giving researchers a powerful new tool to understand one of the biggest mysteries of modern physics.

The DOE's SLAC National Accelerator Laboratory is managing the construction project for the international SuperCDMS collaboration of 111 members from 26 institutions, which is preparing to do research with the experiment.

"Understanding dark matter is one of the hottest research topics - at SLAC and around the world," said JoAnne Hewett, head of SLAC's Fundamental Physics Directorate and the lab's chief research officer. "We're excited to lead the project and work with our partners to build this next-generation ."

With the DOE approvals, known as Critical Decisions 2 and 3, the researchers can now build the experiment. The DOE Office of Science will contribute $19 million to the effort, joining forces with the National Science Foundation ($12 million) and the Canada Foundation for Innovation ($3 million).

"Our experiment will be the world's most sensitive for relatively light WIMPs - in a mass range from a fraction of the proton mass to about 10 proton masses," said Richard Partridge, head of the SuperCDMS group at the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC), a joint institute of SLAC and Stanford University. "This unparalleled sensitivity will create exciting opportunities to explore new territory in dark matter research."

An Ultracold Search 6,800 Feet Underground

Scientists know that in the universe accounts for only 15 percent of all matter. The rest is a mysterious substance, called dark matter. Due to its gravitational pull on regular matter, dark matter is a key driver for the evolution of the universe, affecting the formation of galaxies like our Milky Way. It therefore is fundamental to our very own existence.

Construction begins on one of the world's most sensitive dark matter experiments
The SuperCDMS dark matter experiment will be located at the Canadian laboratory SNOLAB, 2 kilometers (6,800 feet) underground inside a nickel mine near the city of Sudbury. It's the deepest underground laboratory in North America. There it will be protected from high-energy particles, called cosmic radiation, which can create unwanted background signals. Credit: Greg Stewart/SLAC National Accelerator Laboratory; inset: SNOLAB

But scientists have yet to find out what dark matter is made of. They believe it could be composed of , and WIMPs are top contenders. If these particles exist, they would barely interact with their environment and fly right through regular matter untouched. However, every so often, they could collide with an atom of our visible world, and dark matter researchers are looking for these rare interactions.

In the SuperCDMS SNOLAB experiment, the search will be done using silicon and germanium crystals, in which the collisions would trigger tiny vibrations. However, to measure the atomic jiggles, the crystals need to be cooled to less than minus 459.6 degrees Fahrenheit - a fraction of a degree above absolute zero temperature. These ultracold conditions give the experiment its name: Cryogenic Dark Matter Search, or CDMS. The prefix "Super" indicates an increased sensitivity compared to previous versions of the experiment.

The collisions would also produce pairs of electrons and electron deficiencies that move through the crystals, triggering additional atomic vibrations that amplify the signal from the dark matter collision. The experiment will be able to measure these "fingerprints" left by dark matter with sophisticated superconducting electronics.

The experiment will be assembled and operated at the Canadian laboratory SNOLAB - 6,800 feet underground inside a nickel mine near the city of Sudbury. It's the deepest underground laboratory in North America. There it will be protected from high-energy particles, called cosmic radiation, which can create unwanted background signals.

"SNOLAB is excited to welcome the SuperCDMS SNOLAB collaboration to the underground lab," said Kerry Loken, SNOLAB project manager. "We look forward to a great partnership and to supporting this world-leading science."

Over the past months, a detector prototype has been successfully tested at SLAC. "These tests were an important demonstration that we're able to build the actual detector with high enough energy resolution, as well as detector electronics with low enough noise to accomplish our research goals," said KIPAC's Paul Brink, who oversees the detector fabrication at Stanford.

Together with seven other collaborating institutions, SLAC will provide the experiment's centerpiece of four detector towers, each containing six crystals in the shape of oversized hockey pucks. The first tower could be sent to SNOLAB by the end of 2018.

Construction begins on one of the world's most sensitive dark matter experiments
The centerpiece of the SuperCDMS SNOLAB experiment will be four detector towers (left), each containing six detector packs. The towers will be mounted inside the SNOBOX (right), a vessel in which the detector packs will be cooled to almost absolute zero temperature. Credit: Greg Stewart/SLAC National Accelerator Laboratory
"The detector towers are the most technologically challenging part of the experiment, pushing the frontiers of our understanding of low-temperature devices and superconducting readout," said Bernard Sadoulet, a collaborator from the University of California, Berkeley.

A Strong Collaboration for Extraordinary Science

In addition to SLAC, two other national labs are involved in the project. Fermi National Accelerator Laboratory is working on the experiment's intricate shielding and cryogenics infrastructure, and Pacific Northwest National Laboratory is helping understand background signals in the experiment, a major challenge for the detection of faint WIMP signals.

A number of U.S. and Canadian universities also play key roles in the experiment, working on tasks ranging from detector fabrication and testing to data analysis and simulation. The largest international contribution comes from Canada and includes the research infrastructure at SNOLAB.

"We're fortunate to have a close-knit network of strong collaboration partners, which is crucial for our success," said KIPAC's Blas Cabrera, who directed the project through the CD-2/3 approval milestone. "The same is true for the outstanding support we're receiving from the funding agencies in the U.S. and Canada."

Fermilab's Dan Bauer, spokesperson of the SuperCDMS collaboration, said, "Together we're now ready to build an experiment that will search for dark matter particles that interact with normal matter in an entirely new region."

SuperCDMS SNOLAB will be the latest in a series of increasingly sensitive dark experiments. The most recent version, located at the Soudan Mine in Minnesota, completed operations in 2015.

"The project has incorporated lessons learned from previous CDMS experiments to significantly improve the experimental infrastructure and detector designs for the experiment," said SLAC's Ken Fouts, project manager for SuperCDMS SNOLAB. "The combination of design improvements, the deep location and the infrastructure support provided by SNOLAB will allow the experiment to reach its full potential in the search for low-mass ."


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May 07, 2018
"The definition of insanity is doing the same thing over and over again and expecting different results."
A. Einstein

May 07, 2018
"The definition of insanity is doing the same thing over and over again and expecting different results."
A. Einstein

Good thing then that they aren't trying to do the same thing, eh? (Which should be readily apparent to you if you'd read the article)

May 07, 2018
"The definition of insanity is doing the same thing over and over again and expecting different results."
A. Einstein
When you have variations or different ways of doing the same thing over and over again, it is no longer 'the same thing'. And yes, you would be entitled to be able to expect different results!

Best Regards, DH66
(Anti, you beat me to it! ;))


May 07, 2018
As I understand, all experiments searching for dark matter attempt to detect a reaction in an atomic nucleus caused by a collision with a particle. This one is no different other than the sensitivity of the measuring device...it really does constitute insanity if Dark matter isn't a particle, given the number of failed experiments thus far. But if this one is successful, congratulations to the team who came with the approach that refined the sensitivity to this level.

May 07, 2018
As I understand, all experiments searching for dark matter attempt to detect a reaction in an atomic nucleus caused by a collision with a particle.

...each at different energies. The experiments are tailored to look in different sectors of what dark matter could be.

Imagine we're blind but we know something is there. However we know how to build a machine that looks for something red. When that doesn't turn anything up we build a machine that looks for something blue, etc. . It would only be insanity if we would keep building machines that look for something red over and over again.

May 07, 2018
The insane are running this asylum, and their acolytes are posting comments. They could be using the Super-Duper Fantrabulastic Faerie Dust Detector Array, they still will not find anything because there is no dark matter. It's a pie in the sky pipedream of plasma ignoramuses who don't understand that EM drives these systems, not puny gravitational effects.

May 07, 2018
"at different energies"

If a substance is transparent to EM energy as DM has thus far proven to be, assuming it to have an EM energy value is a guess (although a good one if it exists in our universe, but a bad one as it shouldn't exhibit transparency to all spectrums if it does have said energy content).

"keep building machines that look for something red over and over again"

One could transpose the words "red" and "particulate" in your analogy. I'm not trying to be contentious, but all of the devices we have built have been searching for particles reacting the same way. Since this particle, if it exists, only seems to react gravitationally, perhaps an experiment designed around a finite mass and sensors which measure fluctuations in the mass value...a DM particle would pass through said mass and theoretically increase it's gravitational attraction in a measurable fashion. Still a search for a particle, but applying the one "known" property DM appears to have.


May 07, 2018
perhaps an experiment designed around a finite mass and sensors which measure fluctuations in the mass value

We already know it has mass, so making a machine that measures mass doesn't tell us anything new.

Also - not to put too fine a point on it - the kinds of mass interaction our most sensitive devices can measure are so many orders of magnitude above what a DM particle would elicit it isn't even funny. Unless you have some cool idea how to make such devices about 25 orders of magnitude(!) better that is.

May 07, 2018
Over 40 years of looking for hypothetical subatomic particle dark matter.

Not one shred of evidence found for any of the unicorn particles.

They still think WIMPS or axions or some other unicorn comprises the dark matter.

In my book, and Einstein's, that is insanity. It's also poor science. When tests yield negative results. "We need a bigger detector" should not be your only conclusion. One should consider different possible answers and approaches to the problem.

May 07, 2018
"We already know it has mass, so making a machine that measures mass doesn't tell us anything new."

But a measured mass fluctuation that could only come from a slight increase in gravity would tell us one just passed through...which as I understand would be a lot more than anything else has done so far. As to the tech required....you are right, it doesn't exist. It was more about the approach....as in something different in the event this latest attempt ends the same way all of the others have.

May 07, 2018
It's also poor science. When tests yield negative results. "We need a bigger detector" should not be your only conclusion. One should consider different possible answers and approaches to the problem.


They are considered. However building a bigger detector should also be part of the conclusion. Otherwise is it poor science.

May 07, 2018
Over 40 years of looking for hypothetical subatomic particle dark matter

Well, we spent roughly 2000 years looking for atoms (from first idea that they should exits to when we had the first clear pictures of them)...so...meh.

They still think WIMPS or axions or some other unicorn comprises the dark matter.

Surprising as this may sound: There's still quite a few things science doesn't know. That's why people are still doing science, you know?

When tests yield negative results. "We need a bigger detector"

No. We need a *different* detector. When you don't find something in possible place A then you go look in possible place B. That's exactly what they're doing. There's just no definite method to go "it must be there". If you look at other searches (e.g. for the Higgs boson, or neutrinos) then it was the same way. There are many possibilities and you just have to try them until you either find it or run out of ideas where to look.

May 07, 2018
There is evidence of dark matter every time a double-slit experiment is performed, as it is the medium that waves.

May 07, 2018
It doesn't matter, one great day a wise scientist will come along and flip this blip on its head, and we'll have realized these instruments were actually searching for a better model! Still, science is mostly about making errors and learning from them!

May 07, 2018
To paraphrase Thomas Edison, he discovered a thousand ways to NOT build a commercially viable light bulb.

However the eventual result was a working, profitable technology.

A physical result that escapes the capabilities of the anti-DM crowd.

True, I am one of those who have disparaged the existence of the phenomena mene-entitled "Dark Matter".

I also have no physical results to show for my opposition. It's just been too much fun to give up ragging on all of you with my crankery.

May 07, 2018
I hope that they will be able to detect neutrinos and predicted neutrino-like particles, because that is the source of dark energy and its dark matter effect. I have published this on Quora.

May 07, 2018
We looked for the Higgs boson for forty years after ten years of fussing around deciding exactly what to look for. We used progressively bigger and bigger particle accelerators. Eventually we built one big enough and we found it. The newspapers made a big deal about it for a week or two and then moved on. It was one of the most definitive experiments in the history of particle physics; the Higgs field accounts for particles' masses, and for the short range of the weak nuclear force, as well as the broken symmetry of weak isospin.

The Higgs would have been detected in the 1980s at the latest if we had built the SSC (Superconducting Super Collider, AKA Desertron) proposed in the 1970s. People called it a unicorn when the congresscritters killed the SSC. Teh stupid, it burnz.

Just sayin'.

May 07, 2018
Why can't we give people a zero for saying something really stupid? Like for example we should stop looking for WIMPs, or Einstein was wrong, or the universe is made of electricity?

Just askin'.

May 07, 2018
The significance of this experiment is that we've now advanced detection capabilities to find a WIMP if it's near (under or a bit over) the mass of a proton. Previous detectors haven't had the sensitivity to look in this mass sector; saying we shouldn't look here for WIMPs is like saying we shouldn't look in particularly dark parts of the forest for unicorns because everybody's scared to look there. What you're afraid of is that we'll find something. Get over it. Grow a pair. Stop whining.

May 07, 2018
Whereas the actual detection of dark matter is so easy, every electroamateour can do it in his kitchen


........really? How can we do this in our kitchen?

For old man schneibo, why wouldn't a full length body mirror somewhere else work just as well? He could simply stand in front of it & turn sideways, VOILA.......locally produced DM now discovered. He could then send the details of his discovery to the committee that evaluates candidates for the Nobel Prize, and yet another VOILA, little old man discovers the greatest hidden secret of the Universe under his beltline.

May 07, 2018
And here come the primary whiners. What's the deal here, you figure if you keep whining enough everyone will forget you're whining? That's how the four-year-old figures lying about the cookie crumbs on the front of the sweater.

May 07, 2018
I still find it funny how one experiment (MMX) was enough to say the ether does not exist, but here countless of null experiments for dark matter continue unabated. The money must be really good.

May 07, 2018
I still find it funny how one experiment (MMX) was enough to say the ether does not exist, but here countless of null experiments for dark matter continue unabated. The money must be really good.

Ether is a singular theory. It makes a definite prediction. So you can destroy it with one experiment when that prediction doesn't hold.

Dark matter is not a singular theory. There are many contesting theories: WIMPs, MACHOs, axions, sterile neutrinos.... and even stuff like WIMPs are not a singular theory as there are several WIMP variants differentiated by the energy of the particle - which is why there are several different test setups required to find/disprove those because different theories make different predictions.

(And no. The money isn't good. A scientist's salary is pretty shitty - at least compared to what someone with that kind of a degree can easily earn in a private company. From my own experience it's about a factor of 4)

May 07, 2018
Sorry, I'm not buying it. Those sound like convenient excuses.

The ether was not a "singular" theory. There were many theories trying to describe it, you need simply read them. ... (if the ether is entrenched, the mmx is a silly experiment)

Consider how current experiments in condensed matter appear to show very similar properties to components of the ether. But if one does not wish to learn that is not anyone else's problem. I have noticed the poor state of curiosity in modern "researchers", its as though their motto is "if we don't understand it, we won't research it", and yes this is from personal experience of having to deal with them.

May 07, 2018
The ether was not a "singular" theory.
Ether is Dark Matter, the reason you know is because no can find any of it to prove it isn't, vice versa. You see, when you come to a fork in the road.....take it!!!

May 08, 2018
Dark matter is constantly falling on the Sun. I read a paper today saying axion quark nugget dark matter releases enough energy to explain the temperature of the corona. The Sun could be our best DM detector!!!

May 08, 2018
Sorry, I'm not buying it.

That's just the way it is. If you don't like it or don't understand it or aren't willing to put in a little time (actually less time than it toolk you to write your post) reading up on it then...meh...your opinion isn't worth diddly-squat.

The ether was not a "singular" theory.

All of them made the same prediction: That the Earth was moving through it. So if you show that that can't be true all of the ether theories go out the window. The Michelson-Morley experiment did that.

Consider how current experiments in condensed matter appear to show very similar properties to components of the ether.

Erm...no they don't. You're just making shit up, now.

its as though their motto is "if we don't understand it, we won't research it"

Lemme get this straight: You're griping about them building detectors to research stuff they don't understand and then you accuse them of not wanting to research stuff they don't understand?

May 08, 2018
nd yes this is from personal experience of having to deal with them.

...ahahhahahahhaha...hahhaha...oh my...hahahah...thanks for that laugh. No. You've never even been near a scientist let alone dared to speak to one because then you wouldn't make such stupid statements.

Oh man *wipes aways tears of laughter*...you really thought you would get away with a statement like that? Really? Seriously, dude? How far gone do you have to be to think anyone will fall for that?

May 08, 2018
No. You've never even been near a scientist let alone dared to speak to one
Scientists ride in uber cars too, no?
I'm not buyin it
Well would you buy this then?

"Brilliant Light Power has developed a new commercially competitive, non-polluting, plasma-based primary source of massive power from the conversion of hydrogen atoms of water molecules to DARK MATTER, the previously unidentified matter that makes up most of the mass of the universe. The SunCell® that was invented to harness the new power source catalytically converts hydrogen directly into DARK MATTER form called Hydrino®..."

-??

Cheap now but could get very expensive very soon-

May 08, 2018
Dark matter is constantly falling on the Sun.

Since dark matter doesn't seem to interact (strongly) with the 'regular' kind of matter - other than through gravitation - it wouldn't fall into the sun but through it.
If you look at a system of massive DM particle that is somewhere outside a massive object (other than a black hole for obvious reasons) :
Such a particle would oscillate endlessly through this mass without any reduction in amplitude.

I read a paper today saying axion quark nugget dark matter releases enough energy to explain the temperature of the corona.

DM seems to interact even weaker than neutrinos. How should that energy be transferred to the corona? Also: Why the corona and not places like the sun's surface which is significantly cooler?

May 08, 2018
"The definition of insanity is doing the same thing over and over again and expecting different results."
A. Einstein


This must refer to Alfred Einstein, as Albert Einstein did not ever say this. It runs completely counter to the notion of verification or results and is the world's best mantra for a miserable life. Fail once? Quit, and tell other people not to try.

May 08, 2018

Oh man *wipes aways tears of laughter*...you really thought you would get away with a statement like that? Really? Seriously, dude? How far gone do you have to be to think anyone will fall for that?


I am reminded of Bill Murray's quote: "It's hard to win an argument with a smart person, but it's damn near impossible to win an argument with a stupid person."

Or rather, I don't respond to paid shills.

May 22, 2018
At a certain galactic distance, gravity reverses and the galaxies begin pushing against each other. Thus no need for cosmological expansion, dark matter, or dark energy.
A revised gravity equation:

F = (1.047 X 10^-17) m1m2 [-cos(Θ)] / r^2 where tan Θ = r / (1.419 X 10^22)

Playing with the constants, this equation can be fitted and tested against the data of galactic motion. It means that at a certain distance, gravity will reverse and the galaxies will be pushing against each other. This pressure against each other does away with the need for dark matter or dark energy.

The constants may have to be adjusted to fit the data, but this equation will account for galactic motion. Please take a look at the explanation in this theory. In this article I explain why gravity behaves this way:

https://www.reddi...tter_is/

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