From Tohoku University[東北大学](JP): “Mushrooms and their Post-rain Electrical Conversations”

From Tohoku University[東北大学](JP)

4.28.23

Yu Fukasawa
Kawatabi Field Science Center,
Tohoku University
yu.fukasawa.d3tohoku.ac.jp

Mushrooms.

Certain fungi play a critical role in the ecological sustenance of forest trees. Ectomycorrhizal fungi are one such example. Commonly found on pine, oak, and birch trees, ectomycorrhizal fungi form a sheath around the outside of tree roots, and their mycelial body develops into vast underground networks that absorb vital nutrients from the soil and transfer it to the trees.

Scientists have been studying the possibility of electrical signal transfer between mushrooms and across trees via the mycelial networks. It is thought that fungi generate electrical signals in response to external stimuli and use these signals to communicate with each other, coordinating growth and other behavior. It has even been hypothesized that these signals can be used to help transfer nutrients to plants and trees.

Still, current scientific evidence remains sparse. Moreover, many studies have been limited to the laboratory, failing to recreate what happens in the wild.

Now, a group of researchers has recently headed to the forest floor to examine small, tan-colored ectomycorrhizal mushrooms known as Laccaria bicolor. Attaching electrodes to six mushrooms in a cluster, the researchers discovered that the electrical signals increased after rainfall.

Mushrooms in the field with an electrode attached to the top and bottom. © Yu Fukasawa.

“In the beginning, the mushrooms exhibited less electrical potential, and we boiled this down to the lack of precipitation,” says Yu Fukasawa from Tohoku University, who lead the project along with Takayuki Takehi and Daisuke Akai from the National Institute of Technology, Nagaoka College, and Masayuki Ushio from the Hakubi Center, Kyoto University (presently at the Hong Kong University of Science and Technology). “However, the electrical potential began to fluctuate after raining, sometimes going over 100 mV.”

The researcher correlated this fluctuation with precipitation and temperature, and causality analysis revealed that the post-rain electric potential showed signal transport among mushrooms. This transport was particularly strong between spatially close mushrooms and demonstrated directionality.

“Our results confirm the need for further studies on fungal electrical potentials under a true ecological context,” adds Fukasawa.

Details of their research were reported in the journal Fungal Ecology on March 14, 2023.

Fungal Ecology

See the full article here.

Comments are invited and will be appreciated, especially if the reader finds any errors which I can correct. Use “Reply”.

five-ways-keep-your-child-safe-school-shootings

Please help promote STEM in your local schools.

Stem Education Coalition

Tohoku University (東北大学](JP), located in Sendai, Miyagi in the Tōhoku Region, Japan, is a Japanese national university. It was the third Imperial University in Japan, the first three Designated National University along with the The University of Tokyo[(東京大] (JP) and Kyoto University [京都大学](JP) and selected as a Top Type university of Top Global University Project by the Japanese government. In 2020 and 2021, the Times Higher Education Tohoku University was ranked No. 1 university in Japan.

In 2016, Tohoku University had 10 faculties, 16 graduate schools and 6 research institutes, with a total enrollment of 17,885 students. The university’s three core values are “Research First [研究第一主義],” “Open-Doors [門戸開放],” and “Practice-Oriented Research and Education [実学尊重].”

Faculties

Arts and Letters
Education
Law
Economics
Science
Medicine
Dentistry
Pharmaceutical Sciences
Engineering
Mechanical and Aerospace Engineering
Information and Intelligent Systems
Applied Chemistry, Chemical Engineering and Bio molecular Engineering
Materials Science and Engineering
Civil Engineering and Architecture
Agriculture

Graduate Schools

Arts and Letters
Education
Law
Economics and Management
Science
Medicine
Dentistry
Pharmaceutical Sciences
Engineering
Agricultural Sciences
International Cultural Studies
Information Sciences
Life Sciences
Environmental Studies
Educational Informatics Research Division / Education Division

Professional graduate schools

Law School
School of Public Policy
Accounting School

Research institutes

Research Institute of Electrical Communication [電気通信研究所]
Institute of Development, Aging and Cancer [加齢医学研究所]
Institute of Fluid Science [流体科学研究所]
Institute for Materials Research,IMR [金属材料研究所]

National Collaborative Research Institute

Institute of Multidisciplinary Research for Advanced Materials [多元物質科学研究所]

International Research Institute of Disaster Science [災害科学国際研究所]

From Tohoku University[東北大学](JP): “Research News – Gamma-Ray Bursts’ Hidden Energy”

From Tohoku University[東北大学](JP)

12.19.22
Kenji Toma,
Frontier Research Institute for Interdisciplinary Sciences
Tohoku University
tomafris.tohoku.ac.jp

Gamma-ray burst. Credit: Cruz Dewilde/ NASA SWIFT.

Gamma-ray bursts are the most luminous explosions in the universe, allowing astrologists [?] to observe intense gamma rays in short durations. Gamma-ray bursts are classified as either short or long, with long gamma-ray bursts being the result of massive stars dying out. Hence why they provide hidden clues about the evolution of the universe.

Gamma-ray bursts emit gamma rays as well as radio waves, optical lights, and X-rays. When the conversion of explosion energy to emitted energy, i.e., the conversion efficiency, is high, the total explosion energy can be calculated by simply adding all the emitted energy. But when the conversion efficiency is low or unknown, measuring the emitted energy alone is not enough.

Now, a team of astrophysicists has succeeded in measuring a gamma-ray burst’s hidden energy by utilizing light polarization. The team was led by Dr. Yuji Urata from the National Central University in Taiwan and MITOS Science CO., LTD and Professor Kenji Toma from Tohoku University’s Frontier Research Institute for Interdisciplinary Sciences (FRIS).

Details of their findings were published in the journal Nature Astronomy [below] on December 8, 2022.

When an electromagnetic wave is polarized, it means that the oscillation of that wave flows in one direction. While light emitted from stars is not polarized, the reflection of that light is. Many everyday items such as sunglasses and light shields utilize polarization to block out the glare of lights traveling in a uniform direction.

Measuring the degree of polarization is referred to as polarimetry. In astrophysical observations, measuring a celestial object’s polarimetry is not as easy as measuring its brightness. But it offers valuable information on the physical conditions of objects.

The team looked at a gamma-ray burst which occurred on December 21, 2019 (GRB191221B). Using the Very Large Telescope of the European Southern Observatory and Atacama Large Millimeter/submillimeter Array – some of the world’s most advanced optical and radio telescopes – they calculated the polarimetry of fast-fading emissions from GRB191221B.

The European Southern Observatory [La Observatorio Europeo Austral][Observatoire européen austral][Europäische Südsternwarte](EU)(CL), Very Large Telescope at Cerro Paranal in the Atacama Desert •ANTU (UT1; The Sun ) •KUEYEN (UT2; The Moon ) •MELIPAL (UT3; The Southern Cross ), and •YEPUN (UT4; Venus – as evening star). Elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo.

The European Southern Observatory [La Observatorio Europeo Austral] [Observatoire européen austral][Europäische Südsternwarte](EU)(CL)/National Radio Astronomy Observatory/National Astronomical Observatory of Japan(JP) ALMA Observatory (CL).

They then successfully measured the optical and radio polarizations simultaneously, finding the radio polarization degree to be significantly lower than the optical one.

“This difference in polarization at the two wavelengths reveals detailed physical conditions of the gamma-ray burst’s emission region,” said Toma. “In particular, it allowed us to measure the previously unmeasurable hidden energy.”

When accounting for the hidden energy, the team revealed that the total energy was about 3.5 times bigger than previous estimates.

With the explosion energy representing the gravitational energy of the progenitor star, being able to measure this figure has important ramifications for determining stars’ masses.

“Knowing the measurements of the progenitor star’s true masses will help in understanding the evolutionary history of the universe,” added Toma. “The first stars in the universe could be discovered if we can detect their long gamma-ray bursts.”

Science paper:
Nature Astronomy

See the full article here.

Comments are invited and will be appreciated, especially if the reader finds any errors which I can correct. Use “Reply”.

five-ways-keep-your-child-safe-school-shootings

Please help promote STEM in your local schools.

Stem Education Coalition

Tohoku University (東北大学](JP), located in Sendai, Miyagi in the Tōhoku Region, Japan, is a Japanese national university. It was the third Imperial University in Japan, the first three Designated National University along with the The University of Tokyo[(東京大] (JP) and Kyoto University [京都大学](JP) and selected as a Top Type university of Top Global University Project by the Japanese government. In 2020 and 2021, the Times Higher Education Tohoku University was ranked No. 1 university in Japan.

In 2016, Tohoku University had 10 faculties, 16 graduate schools and 6 research institutes, with a total enrollment of 17,885 students. The university’s three core values are “Research First [研究第一主義],” “Open-Doors [門戸開放],” and “Practice-Oriented Research and Education [実学尊重].”

Faculties

Arts and Letters
Education
Law
Economics
Science
Medicine
Dentistry
Pharmaceutical Sciences
Engineering
Mechanical and Aerospace Engineering
Information and Intelligent Systems
Applied Chemistry, Chemical Engineering and Bio molecular Engineering
Materials Science and Engineering
Civil Engineering and Architecture
Agriculture

Graduate Schools

Arts and Letters
Education
Law
Economics and Management
Science
Medicine
Dentistry
Pharmaceutical Sciences
Engineering
Agricultural Sciences
International Cultural Studies
Information Sciences
Life Sciences
Environmental Studies
Educational Informatics Research Division / Education Division

Professional graduate schools

Law School
School of Public Policy
Accounting School

Research institutes

Research Institute of Electrical Communication [電気通信研究所]
Institute of Development, Aging and Cancer [加齢医学研究所]
Institute of Fluid Science [流体科学研究所]
Institute for Materials Research,IMR [金属材料研究所]

National Collaborative Research Institute

Institute of Multidisciplinary Research for Advanced Materials [多元物質科学研究所]

International Research Institute of Disaster Science [災害科学国際研究所]

From Tohoku University[東北大学](JP): “Researchers Develop a Scaled-up Spintronic Probabilistic Computer”

From Tohoku University[東北大学](JP)

12.7.22
Shunsuke Fukami
Research Institute of Electrical Communication
s-fukamitohoku.ac.jp

The spintronic path.

Researchers at Tohoku University, the University of Messina, and The University of California-Santa Barbara have developed a scaled-up version of a probabilistic computer (“p-computer”) with stochastic spintronic devices that is suitable for hard computational problems like combinatorial optimization and machine learning.

“Moore’s law” predicts that computers get faster every two years because of the evolution of semiconductor chips. Whilst this is what has historically happened, the continued evolution is starting to lag. The revolutions in machine learning and artificial intelligence means much higher computational ability is required. Quantum computing is one way of meeting these challenges, but significant hurdles to the practical realization of scalable quantum computers remain.

A “p-computer” harnesses naturally stochastic building blocks called probabilistic bits (p-bits). Unlike bits in traditional computers, “P-bits” oscillate between states. A “p-computer” can operate at room-temperature and acts as a domain-specific computer for a wide variety of applications in machine learning and artificial intelligence. Just like quantum computers try to solve inherently quantum problems in quantum chemistry, “p-computers” attempt to tackle probabilistic algorithms widely used for complicated computational problems in combinatorial optimization and sampling.

Recently, researchers from Tohoku University, Purdue University, and The University of California-Santa Barbara have shown that the “p-bits” can be efficiently realized using suitably modified “spintronic” devices called stochastic magnetic tunnel junctions (“sMTJ”). Until now, “sMTJ”-based “p-bits” have been implemented at small scale; and only “spintronic” “p-computer” proof-of-concepts for combinatorial optimization and machine learning have been demonstrated.

A photograph of the constructed heterogeneous “p-computer” consisting of stochastic magnetic tunnel junction (“sMTJ”) based probabilistic bit (“p-bit’) and field-programmable gate array (“FPGA”). ©Kerem Camsari, Giovanni Finocchio, and Shunsuke Fukami et al.

The research group has presented two important advances at the 68th International Electron Devices Meeting (IEDM) on December 6th, 2022.

First, they have shown how “sMTJ”-based “p-bits” can be combined with conventional and programmable semiconductor chips, namely, Field-Programmable-Gate-Arrays (“FPGAs”). The “sMTJ + FPGA” combination allows much larger networks of “p-bits” to be implemented in hardware going beyond the earlier small-scale demonstrations.

Second, the probabilistic emulation of a quantum algorithm, simulated quantum annealing (“SQA”), has been performed in the heterogeneous “sMTJ + FPGA” p-computers with systematic evaluations for hard combinatorial optimization problems.

The researchers also benchmarked the performance of “sMTJ”-based “p-computers” with that of classical computing hardware, such as graphics processing units (GPUs) and Tensor Processing Units (“TPUs”). They showed that “p-computers”, utilizing a high-performance “sMTJ” previously demonstrated by a team from Tohoku University, can achieve massive improvements in throughput and power consumption than conventional technologies.

“Currently, the “s-MTJ + FPGA” “p-computer” is a prototype with discrete components,” said Professor Shunsuke Fukami, who was part of the research group. “In the future, integrated “p-computers” that make use of semiconductor process-compatible magnetoresistive random access memory (“MRAM”) technologies may be possible, but this will require a co-design approach, with experts in materials, physics, circuit design and algorithms needing to be brought in.”

A comparison of probabilistic accelerators as a function of sampling throughput and power consumption. Graphics Processing Units (GPUs) [plotted as N1-N4], Tensor Processing Units (“TPUs”) [plotted as G1-G2], and simulated annealing machine [plotted as F1] are compared with probabilistic computers, where demonstrated value and projected value are plotted as P1 and P2, respectively. ©Kerem Camsari, Giovanni Finocchio, and Shunsuke Fukami et al.

Publication Details:

Title: “Experimental evaluation of simulated quantum annealing with MTJ-augmented p-bits”
Authors: Andrea Grimaldi, Kemal Selcuk, Navid Anjum Aadit, Keito Kobayashi, Qixuan Cao, Shuvro Chowdhury, Giovanni Finocchio, Shun Kanai, Hideo Ohno, Shunsuke Fukami and Kerem Y. Camsari
Conference: 68th Annual IEEE International Electron Devices Meeting

See the full article here.

Comments are invited and will be appreciated, especially if the reader finds any errors which I can correct. Use “Reply”.

five-ways-keep-your-child-safe-school-shootings

Please help promote STEM in your local schools.

Stem Education Coalition

Tohoku University (東北大学](JP), located in Sendai, Miyagi in the Tōhoku Region, Japan, is a Japanese national university. It was the third Imperial University in Japan, the first three Designated National University along with the The University of Tokyo[(東京大] (JP) and Kyoto University [京都大学](JP) and selected as a Top Type university of Top Global University Project by the Japanese government. In 2020 and 2021, the Times Higher Education Tohoku University was ranked No. 1 university in Japan.

In 2016, Tohoku University had 10 faculties, 16 graduate schools and 6 research institutes, with a total enrollment of 17,885 students. The university’s three core values are “Research First [研究第一主義],” “Open-Doors [門戸開放],” and “Practice-Oriented Research and Education [実学尊重].”

Faculties

Arts and Letters
Education
Law
Economics
Science
Medicine
Dentistry
Pharmaceutical Sciences
Engineering
Mechanical and Aerospace Engineering
Information and Intelligent Systems
Applied Chemistry, Chemical Engineering and Bio molecular Engineering
Materials Science and Engineering
Civil Engineering and Architecture
Agriculture

Graduate Schools

Arts and Letters
Education
Law
Economics and Management
Science
Medicine
Dentistry
Pharmaceutical Sciences
Engineering
Agricultural Sciences
International Cultural Studies
Information Sciences
Life Sciences
Environmental Studies
Educational Informatics Research Division / Education Division

Professional graduate schools

Law School
School of Public Policy
Accounting School

Research institutes

Research Institute of Electrical Communication [電気通信研究所]
Institute of Development, Aging and Cancer [加齢医学研究所]
Institute of Fluid Science [流体科学研究所]
Institute for Materials Research,IMR [金属材料研究所]

National Collaborative Research Institute

Institute of Multidisciplinary Research for Advanced Materials [多元物質科学研究所]

International Research Institute of Disaster Science [災害科学国際研究所]

From Tohoku University[東北大学](JP): “Rare Earth Elements Synthesis Confirmed in Neutron Star Mergers”

From Tohoku University[東北大学](JP)

10.27.22 [Just today in social media.]

Neutron Star Merger.

A group of researchers has, for the first time, identified rare earth elements produced by neutron star mergers.

Details of this milestone were published in The Astrophysical Journal [below] on October 26, 2022.

When two neutron stars spiral inwards and merge, the resulting explosion produces a large amount of heavy elements that make up our Universe. The first confirmed example of this process was an event in 2017 named GW 170817. Yet, even five years later, identifying the specific elements created in neutron star mergers has eluded scientists, except for strontium identified in the optical spectra.

A research group led by Nanae Domoto, a graduate student at the Graduate School of Science at Tohoku University and a research fellow at the Japan Society for the Promotion of Science (JSPS), has systematically studied the properties of all heavy elements to decode the spectra from neutron star mergers.

They used this to investigate the spectra of kilonova – bright emissions caused by the radioactive decay of freshly synthesized nuclei that are ejected during the merger – from GW 170817. Based on comparisons of detailed kilonovae spectra simulations, produced by the supercomputer “ATERUI II” at the National Astronomical Observatory of Japan, the team found that the rare elements lanthanum and cerium can reproduce the near-infrared spectral features seen in 2017.

NAOJ ATERUI II Cray XC50 supercomputer located at the National Astronomical Observatory [国立天文台] (JP) (NAOJ).

Until now, the existence of rare earth elements has only been hypothesized based on the overall evolution of the kilonova’s brightness, but not from the spectral features.

“This is the first direct identification of rare elements in the spectra of neutron star mergers, and it advances our understanding of the origin of elements in the Universe,” Dotomo said.

“This study used a simple model of ejected material. Looking ahead, we want to factor in multi-dimensional structures to grasp a bigger picture of what happens when stars collide,” Dotomo added.

The observed spectra of a kilonova (gray) and model spectra obtained in this study (blue). The numbers on the left show the days after the neutron star merger occurred. Dashed lines indicate the features of the absorption lines. The names of the elements that produce these features are shown in the same colors with the dashed lines. The spectra are vertically shifted for visualization. The observed spectra around 1400 nanometer and 1800-1900 nanometer are affected by the earth’s atmosphere. © Nanae Domoto.

Science paper:
The Astrophysical Journal
See the science paper for instructive material with images.

See the full article here.

Comments are invited and will be appreciated, especially if the reader finds any errors which I can correct. Use “Reply”.

five-ways-keep-your-child-safe-school-shootings

Please help promote STEM in your local schools.

Stem Education Coalition

Tohoku University (東北大学](JP), located in Sendai, Miyagi in the Tōhoku Region, Japan, is a Japanese national university. It was the third Imperial University in Japan, the first three Designated National University along with the The University of Tokyo[(東京大] (JP) and Kyoto University [京都大学](JP) and selected as a Top Type university of Top Global University Project by the Japanese government. In 2020 and 2021, the Times Higher Education Tohoku University was ranked No. 1 university in Japan.

In 2016, Tohoku University had 10 faculties, 16 graduate schools and 6 research institutes, with a total enrollment of 17,885 students. The university’s three core values are “Research First [研究第一主義],” “Open-Doors [門戸開放],” and “Practice-Oriented Research and Education [実学尊重].”

Faculties

Arts and Letters
Education
Law
Economics
Science
Medicine
Dentistry
Pharmaceutical Sciences
Engineering
Mechanical and Aerospace Engineering
Information and Intelligent Systems
Applied Chemistry, Chemical Engineering and Bio molecular Engineering
Materials Science and Engineering
Civil Engineering and Architecture
Agriculture

Graduate Schools

Arts and Letters
Education
Law
Economics and Management
Science
Medicine
Dentistry
Pharmaceutical Sciences
Engineering
Agricultural Sciences
International Cultural Studies
Information Sciences
Life Sciences
Environmental Studies
Educational Informatics Research Division / Education Division

Professional graduate schools

Law School
School of Public Policy
Accounting School

Research institutes

Research Institute of Electrical Communication [電気通信研究所]
Institute of Development, Aging and Cancer [加齢医学研究所]
Institute of Fluid Science [流体科学研究所]
Institute for Materials Research,IMR [金属材料研究所]

National Collaborative Research Institute

Institute of Multidisciplinary Research for Advanced Materials [多元物質科学研究所]

International Research Institute of Disaster Science [災害科学国際研究所]

From Tohoku University[東北大学](JP): “Research News”

From Tohoku University[東北大学](JP)

9.30.22

Exploring the Plasma Loading Mechanism of Radio Jets Launched from Black Holes

Figure 2.

Photon spectrum of a reconnection-driven flare from M87. Parameters are M = 6.3 × 109 M⊙, $\dot{m}=5\times {10}^{-5}$, fl = 1.5, and ξhl = 0.5. The blue-dashed, green-dotted, and red-solid lines are for the high-energy flaring state, the low-energy flaring state, and their sum, respectively. The data points are obtained from Table A8 in EHT MWL Science Working Group et al. (2021), which is in the quiescent state. Our model predicts flares of ∼10 times higher luminosity. The black- and gray-dotted lines are sensitivity curves for HiZ-GUNDAM (2 × 104 s: Yonetoku et al. 2020) and AMEGO (106 s: McEnery et al. 2019), respectively.

Figure 3.

Photon spectrum of a reconnection-driven flare from Sgr A* (solid red line). Parameters are M = 4.0 × 106 M⊙, $\dot{m}=6\times {10}^{-7}$, fl =0.6, and ξhl = 0.5. The X-ray flare data (cyan and magenta regions) are taken from Nowak et al. (2012) and Barrière et al. (2014), respectively. The black-dashed line is the sensitivity curve for FORCE (100 s: Nakazawa et al. 2018).

See the science paper for instructive images.

Galaxies, including our Milky Way, host supermassive black holes in their centers, and their masses are millions to billions of times larger than the Sun. Some supermassive black holes launch fast-moving plasma outflows which emit strong radio signals, known as radio jets.

Radio jets were first discovered in the 1970s. But much remains unknown about how they are produced, especially their energy source and plasma loading mechanism.

Recently, the Event Horizon Telescope Collaboration uncovered radio images of a nearby black hole at the center of the giant elliptical galaxy M87. The observation supported the theory that the spin of the black hole powers radio jets but did little to clarify the plasma loading mechanism.

Now, a research team, led by Tohoku University astrophysicists, has proposed a promising scenario that clarifies plasma loading mechanism into radio jets.

Recent studies have claimed that black holes are highly magnetized because magnetized plasma inside galaxies carries magnetic fields into the black hole. Then, neighboring magnetic energy transiently releases its energy via magnetic reconnection, energizing the plasma surrounding the black hole. This magnetic reconnection provides the energy source for solar flares.

Plasmas in solar flares give off ultraviolet and X-rays; whereas the magnetic reconnection around the black hole can cause gamma-ray emission since the released energy per plasma particle is much higher than that for a solar flare.

The present scenario proposes that the emitted gamma rays interact with each other and produce copious electron-positron pairs, which are loaded into the radio jets.

This explains the large amount of plasma observed in radio jets, consistent with the M87 observations. Additionally, the scenario makes note that radio signal strengths vary from black hole to black hole. For example, radio jets around Sgr A* – the supermassive black hole in our Milky Way – are too faint and undetectable by current radio facilities.

Also, the scenario predicts short-term X-ray emission when plasma is loaded into radio jets. These X-ray signals are missed with current X-ray detectors, but they are observable by planned X-ray detectors.

“Under this scenario, future X-ray astronomy will be able to unravel the plasma loading mechanism into radio jets, a long-standing mystery of black holes,” points out Shigeo Kimura, lead author of the study.

Details of Kimura and his team’s research were published in The Astrophysical Journal Letters on September 29, 2022.

See the full article here.

five-ways-keep-your-child-safe-school-shootings

Please help promote STEM in your local schools.

Stem Education Coalition

Tohoku University (東北大学](JP), located in Sendai, Miyagi in the Tōhoku Region, Japan, is a Japanese national university. It was the third Imperial University in Japan, the first three Designated National University along with the The University of Tokyo[(東京大] (JP) and Kyoto University [京都大学](JP) and selected as a Top Type university of Top Global University Project by the Japanese government. In 2020 and 2021, the Times Higher Education Tohoku University was ranked No. 1 university in Japan.

In 2016, Tohoku University had 10 faculties, 16 graduate schools and 6 research institutes, with a total enrollment of 17,885 students. The university’s three core values are “Research First [研究第一主義],” “Open-Doors [門戸開放],” and “Practice-Oriented Research and Education [実学尊重].”

Faculties

Arts and Letters
Education
Law
Economics
Science
Medicine
Dentistry
Pharmaceutical Sciences
Engineering
Mechanical and Aerospace Engineering
Information and Intelligent Systems
Applied Chemistry, Chemical Engineering and Bio molecular Engineering
Materials Science and Engineering
Civil Engineering and Architecture
Agriculture

Graduate Schools

Arts and Letters
Education
Law
Economics and Management
Science
Medicine
Dentistry
Pharmaceutical Sciences
Engineering
Agricultural Sciences
International Cultural Studies
Information Sciences
Life Sciences
Environmental Studies
Educational Informatics Research Division / Education Division

Professional graduate schools

Law School
School of Public Policy
Accounting School

Research institutes

Research Institute of Electrical Communication [電気通信研究所]
Institute of Development, Aging and Cancer [加齢医学研究所]
Institute of Fluid Science [流体科学研究所]
Institute for Materials Research,IMR [金属材料研究所]

National Collaborative Research Institute

Institute of Multidisciplinary Research for Advanced Materials [多元物質科学研究所]

International Research Institute of Disaster Science [災害科学国際研究所]

From Tohoku University[東北大学](JP): “Electron Lens Formed by Light- A New Method for Atomic-resolution Electron Microscopes”

From Tohoku University[東北大学](JP)

2022-04-11

Yuuki Uesugi
IMRAM, Tohoku University
uesugi@tohoku.ac.jp

Electron microscopy enables researchers to visualize tiny objects such as viruses, the fine structures of semiconductor devices, and even atoms arranged on a material surface. Focusing down the electron beam to the size of an atom is vital for achieving such high spatial resolution. However, when the electron beam passes through an electrostatic or magnetic lens the rays of electrons exhibit different focal positions depending on the focusing angle and the beam spreads out at the focus. Correcting this “spherical aberration” is costly and complex, meaning that only a select few scientists and companies possess electron microscopes with atomic resolution.

Researchers from Tohoku University have proposed a new method to form an electron lens that uses a light field instead of the electrostatic and magnetic fields employed in conventional electron lenses. A ponderomotive force causes the electrons traveling in the light field to be repelled from regions of high optical intensity. Using this phenomenon, a doughnut-shaped light beam placed coaxially with an electron beam is expected to produce a lensing effect on the electron beam.

A conceptual illustration of the light-field electron lens. An electron beam (blue) receives the focusing force from a doughnut-shaped light beam (red) at the waist position of the light beam. The inset shows details of the waist area. ⒸYuuki Uesugi et al.

The researches theoretically assessed the characteristics of the light-field electron lens formed using a typical doughnut-shaped light beam – known as a Bessel or Laguerre-Gaussian beam. From there, they obtained a simple formula for focal length and spherical aberration coefficients which allowed them to determine rapidly the guiding parameters necessary for the actual electron lens design.

The formulas demonstrated that the light-field electron lens generates a “negative” spherical aberration which opposes the aberration of electrostatic and magnetic electron lenses. The combination of the conventional electron lens with a “positive” spherical aberration and a light-field electron lens that offset the aberration reduced the electron beams size to the atomic scale. This means that the light-field electron lens could be used as a spherical aberration corrector.

“The light-field electron lens has unique characteristics not seen in conventional electrostatic and magnetic electron lenses,” says Yuuki Uesugi, assistant professor at the Institute of Multidisciplinary Research for Advanced Materials at Tohoku University and lead author of the study. “The realization of light-based aberration corrector will significantly reduce installation costs for electron microscopes with atomic resolution, leading to their widespread use in diverse scientific and industrial fields,” adds Uesugi.

Looking ahead, Uesugi and colleagues are exploring ways for the practical application of next-generation electron microscopes using the light-field electron lens.

Results of electronic trajectory calculations. An electron objective lens with a spherical aberration of 1 nanometer was corrected using a light-field electronic lens with the negative spherical aberration. The beam radius at the focus (z = 0) was reduced from 1 nm to the atomic scale of 0.3 nm. ⒸYuuki Uesugi et al.

Science paper:
Journal of Optics

See the full article here.

five-ways-keep-your-child-safe-school-shootings

Please help promote STEM in your local schools.

Stem Education Coalition

Tohoku University (東北大学](JP), located in Sendai, Miyagi in the Tōhoku Region, Japan, is a Japanese national university. It was the third Imperial University in Japan, the first three Designated National University along with the The University of Tokyo[(東京大] (JP) and Kyoto University [京都大学](JP) and selected as a Top Type university of Top Global University Project by the Japanese government. In 2020 and 2021, the Times Higher Education Tohoku University was ranked No. 1 university in Japan.

In 2016, Tohoku University had 10 faculties, 16 graduate schools and 6 research institutes, with a total enrollment of 17,885 students. The university’s three core values are “Research First [研究第一主義],” “Open-Doors [門戸開放],” and “Practice-Oriented Research and Education [実学尊重].”

Faculties

Arts and Letters
Education
Law
Economics
Science
Medicine
Dentistry
Pharmaceutical Sciences
Engineering
Mechanical and Aerospace Engineering
Information and Intelligent Systems
Applied Chemistry, Chemical Engineering and Bio molecular Engineering
Materials Science and Engineering
Civil Engineering and Architecture
Agriculture

Graduate Schools

Arts and Letters
Education
Law
Economics and Management
Science
Medicine
Dentistry
Pharmaceutical Sciences
Engineering
Agricultural Sciences
International Cultural Studies
Information Sciences
Life Sciences
Environmental Studies
Educational Informatics Research Division / Education Division

Professional graduate schools

Law School
School of Public Policy
Accounting School

Research institutes

Research Institute of Electrical Communication [電気通信研究所]
Institute of Development, Aging and Cancer [加齢医学研究所]
Institute of Fluid Science [流体科学研究所]
Institute for Materials Research,IMR [金属材料研究所]

National Collaborative Research Institute

Institute of Multidisciplinary Research for Advanced Materials [多元物質科学研究所]

International Research Institute of Disaster Science [災害科学国際研究所]