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Today's Topics:
1. Q-NEXT "For quantum sensors, diamond is king," (Stephen Loosley)
2. Work Begins On First Generation IV Nuclear Power Plant In US
(Stephen Loosley)
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Message: 1
Date: Sun, 11 Aug 2024 19:25:19 +0930
From: Stephen Loosley <[email protected]>
To: "link" <[email protected]>
Subject: [LINK] Q-NEXT "For quantum sensors, diamond is king,"
Message-ID: <[email protected]>
Content-Type: text/plain; charset="UTF-8"
`
X-ray imagery of vibrating diamond opens avenues for quantum sensing
Atom-scale measurements of diamond lead to new equation related to quantum
sensors
Date: August 7, 2024
Source: DOE/Argonne National Laboratory
Summary: Scientists at three research institutions capture the pulsing motion
of atoms in diamond, uncovering the relationship between the diamond's strain
and the behavior of the quantum information hosted within.
FULL STORY
When it comes to materials for quantum sensors, diamond is the best game in
town, says Cornell University professor Gregory Fuchs.
Now he and a team of scientists have upped diamond's game by generating
exquisite imagery of diamond undergoing microscopic vibrations.
The team, comprising researchers at the U.S. Department of Energy's (DOE)
Argonne National Laboratory, Cornell and Purdue University, achieved a two-fold
advance for quantum information science.
First, pulsing the diamond with sound waves, they took X-ray images of the
diamond's vibrations and measured how much the atoms compressed or expanded
depending on the wave frequency.
Second, they connected that atomic strain with another atomic property, spin --
a special feature of all atomic matter -- and defined the mathematical
relationship between the two.
The findings are key for quantum sensing, which draws on special features of
atoms to make measurements that are significantly more precise than we're
capable of today.
Quantum sensors are expected to see widespread use in medicine, navigation and
cosmology in the coming decades.
Shake and spin
Scientists use spin to encode quantum information.
By determining how spin responds to strain in diamond, the team provided a
manual on how to manipulate it: Give the diamond a microshake in this way, and
the spin shifts this much. Shake the diamond that way, and the spin shifts that
much.
The research, published in Physical Review Applied, is the first time anyone
has directly measured the correlation in diamond at gigahertz frequencies
(billions of pulses per second).
It is also part of a larger effort in the quantum science community to
precisely connect atomic strain and the associated spin in a broad range of
materials.
For example, researchers at Argonne and the University of Chicago previously
measured spin-strain correlations in silicon carbide, another star material
that researchers are engineering for quantum applications.
The group's research is supported in part by Q-NEXT, a DOE National Quantum
Information Science Research Center led by Argonne.
"We're connecting two sides of an equation -- the spin side and the strain side
-- and directly comparing what's going on in the diamond," said Fuchs, a
professor in Cornell's School of Applied and Engineering Physics and a
collaborator within Q-NEXT. "It was very satisfying to directly hammer both of
them down."
Solving the spin-strain equation
The two sides of the equation were hammered down hundreds of miles apart.
For the spin measurements, scientists at Cornell University in New York
measured how spin responded to the sound waves pulsing through the diamond
using a one-of-a-kind device developed by researchers at Cornell and Purdue.
For the strain measurements, Cornell graduate student and paper author Anthony
D'Addario drove 700 miles to Argonne in Illinois to use the Advanced Photon
Source (APS), a DOE Office of Science user facility. The
1-kilometer-circumference machine generates X-rays that allow researchers to
see how a material behaves at the atomic and molecular level. Having generated
images of strain in other materials for quantum technologies, it would now do
the same for diamond. The team used an X-ray beam jointly operated by the APS
and Argonne's Center for Nanoscale Materials, also a DOE Office of Science user
facility, to take strobe-light-like pictures of the diamond's atoms as they
shook back and forth.
They focused on a particular site within the diamond: an irregularity called a
nitrogen vacancy (NV) center, which consists of an atom-sized hole and a
neighboring nitrogen atom. Scientists use NV centers as the basis for quantum
sensors.
The APS's high-resolution images enabled the team to measure the atoms'
movement near the diamond's NV centers to one part in 1,000.
"Being able to use the APS to unambiguously look at or quantify the strain near
the NV center as it's being modulated by these beautiful acoustic resonators
developed at Purdue and Cornell -- that allows us to get the story locally near
the NV centers," said Argonne scientist and Q-NEXT collaborator Martin Holt,
who is also an author on the paper. "That's always been the beauty of hard
X-rays: being able to look entirely through complex systems and get
quantitative answers about what's inside."
With both spin and strain measurements in hand, Fuchs and team related the two
in an equation that, satisfyingly, agreed with theory.
"The most exciting part was in doing the analysis. We ended up finding a new
number that related the spin and strain, and it ended up agreeing with some
theory and previous measurements," D'Addario said.
Acoustic engineering
Spin can be manipulated in a few ways. The most popular is to use
electromagnetic waves. Using acoustic waves is less common.
But it has advantages. For one, acoustic waves can be used to manipulate spin
in ways that can't be achieved with electromagnetic fields.
For another, acoustic waves can protect the quantum information encoded in the
spin. Quantum information is fragile and falls apart when disturbed by its
environment, a process called decoherence. One of the aims of quantum research
is to stave off decoherence long enough for the information to be processed
successfully.
"It's a little counterintuitive that adding sound to a system makes it better,
but it's a bit like turning on a white noise generator to not hear a
conversation," Holt said. "You can use the acoustic waves to protect the
quantum bit from decoherence. You're shifting what the system is sensitive to
in a way that protects it from these other sound processes."
There's also the advantage of miniaturization. Whereas a 1-gigahertz
electromagnetic wave is roughly a foot long, a gigahertz acoustic wave is tiny,
about the width of a human hair. That small wavelength allows scientists to
place multiple similar devices in a small setup and still ensure that their
signals won't cross each other.
"If you want there not to be a lot of discussion or interference between
neighboring devices, then you can use acoustic-wave devices, which can be very
confined," Fuchs said.
Combining these advantages with diamond makes for a superior quantum sensor. As
a host for quantum information, diamond enables long information lifetimes, can
operate at room temperature and provides reliable measurements.
"I would say most people would agree with me that, for quantum sensors, diamond
is king," Fuchs said.
Cross-discipline collaboration was key to the effort.
"Because of the complexity and sensitivity of these systems, there are many
different things that can move quantum phenomena around," Holt said. "Being
able to carefully baseline the response to individual pieces requires
correlation. That's a multidisciplinary question, and that's something that
Q-NEXT is very well-suited to answer."
"The investment of Q-NEXT in terms of creating in-operation environments for
quantum systems in these facilities is really paying off."
This work was supported by the DOE of Science National Quantum Information
Science Research Centers as part of the Q-NEXT center.
Story Source:
Materials provided by DOE/Argonne National Laboratory. Original written by Leah
Hesla. Note: Content may be edited for style and length.
Journal Reference:
Anthony D?Addario, Johnathan Kuan, Noah F. Opondo, Ozan Erturk, Tao Zhou, Sunil
A. Bhave, Martin V. Holt, Gregory D. Fuchs. Stroboscopic x-ray diffraction
microscopy of dynamic strain in diamond thin-film bulk acoustic resonators for
quantum control of nitrogen-vacancy centers. Physical Review Applied, 2024; 22
(2) DOI: 10.1103/PhysRevApplied.22.024016
Cite This Page: DOE/Argonne National Laboratory. "X-ray imagery of vibrating
diamond opens avenues for quantum sensing."
ScienceDaily. ScienceDaily, 7 August 2024.
<www.sciencedaily.com/releases/2024/08/240807122901.htm>.
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Message: 2
Date: Sun, 11 Aug 2024 19:43:11 +0930
From: Stephen Loosley <[email protected]>
To: "link" <[email protected]>
Subject: [LINK] Work Begins On First Generation IV Nuclear Power Plant
In US
Message-ID: <[email protected]>
Content-Type: text/plain; charset="UTF-8"
Work Begins On First Generation IV Nuclear Power-Plant In US
By David Dalton 31 July 2024
https://www.nucnet.org/news/work-begins-on-first-generation-iv-nuclear-power-plant-in-us-7-3-2024
Kairos Power?s Hermes low-power demonstration unit could be operational at Oak
Ridge site in 2027
Kairos Power has started construction on one of the first advanced reactors in
the US in what the California-based company called a ?critical milestone? on
its path to commercialising advanced reactor technology.
Kairos Power said in a statement that the Hermes Low-Power Demonstration
Reactor, which could be operational in 2027, is the first and only Generation
IV* reactor to be approved for construction by the US Nuclear Regulatory
Commission (NRC) and the first non-light-water reactor to be permitted in the
US in over 50 years.
Hermes is a non-power version of Kairos Power?s fluoride salt-cooled high
temperature reactor, the KP-HFR.
Kairos Power said it had recently started excavation and groundwork at the
Hermes site in Oak Ridge, Tennessee, through a contract with Montana-based
Barnard Construction Company.
The US Department of Energy (DOE) said in a statement that the reactor is being
used to inform the development of a commercial reactor that could be deployed
?next decade?.
It said Hermes is one of several projects being supported through the DOE?s
advanced reactor demonstration programme, which is designed to help the
domestic nuclear industry demonstrate its advanced reactor designs and
ultimately help the US build a competitive portfolio of new US reactors that
offer significant improvements over today?s technology.
Kairos Power has committed to invest at least $100m (?92m) to support Hermes?
construction and operation.
The DOE will invest up to?$303m?in the project through a performance-based
milestone contract funded by advanced reactor demonstration programme to
support Hermes? design, construction, and commissioning.
Hermes will use a Triso fuel pebble bed design with a molten fluoride salt
coolant to demonstrate ?affordable clean heat production?, the DOE said.
Kairos Power said the reactor?s novel combination of Triso coated particle fuel
and Flibe molten fluoride salt coolant yields robust inherent safety while
simplifying the reactor?s design.
Triso ? or ?tristructural-isotropic? ? fuel particles contain a spherical
kernel of enriched uranium oxycarbide surrounded by layers of carbon and
silicon carbide, which contains fission products.
According to the DOE, Triso is essentially a ?robust, microencapsulated fuel
form? developed originally in the 1950s.
Perhaps Triso?s biggest benefit is that each particle acts ?as its own
containment system thanks to its triple-coated layers,? the DOE said. This
allows them to retain fission products under all reactor conditions.
Triso particles are especially robust. ?Simply put, Triso particles cannot melt
in a reactor and can withstand extreme temperatures that are well beyond the
threshold of current nuclear fuels,? the DOE said.
Transforming Conventional Nuclear Construction
The Hermes project was cleared for construction by the US Nuclear Regulatory
Commission in December.
Kairos Power has also applied for a construction permit for the
electricity-generating Hermes 2 test reactor, which will also be built at Oak
Ridge and will feature two 35 MWt units similar to the Hermes plant.
Barnard and Kairos Power have also started collaborating to build the third
engineering test unit (ETU 3.0) ? a non-nuclear demonstration at Oak Ridge that
will generate supply chain, construction and operational experience for the
Hermes project.
Both Hermes and ETU 3.0 will be built using modular construction techniques
piloted at Kairos Power?s testing and manufacturing campus in Albuquerque, New
Mexico.
Reactor modules will be fabricated in Albuquerque and shipped to Oak Ridge for
assembly, demonstrating the potential of a factory-built small modular reactor
design to transform conventional nuclear construction.
In December 2023 China?s National Energy Administration said China had begun
commercial operation of the first Generation IV plant in the world, the HTR-PM
(high-temperature reactor-pebble-bed modules) plant at Shidao Bay.
* No precise definition of a Generation IV reactor exists, but the term is used
to refer to nuclear reactor technologies under development including gas-cooled
fast reactors, lead-cooled fast reactors, molten salt reactors, sodium-cooled
fast reactors, supercritical-water-cooled reactors and very high-temperature
reactors. An international task force, the Generation IV International Forum
(GIF), is sharing R&D to develop six Generation IV nuclear reactor
technologies. GIF said goals of Generation IV reactor design include lower cost
and financial risk, minimising nuclear waste and high levels of safety and
reliability.
--
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