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Category: nuclear energy – Page 40

New calculation approach allows more accurate predictions of how atoms ionize when impacted by high-energy electrons

During electron-impact ionization (EII), high-energy electrons collide with atoms, knocking away one or more of their outer electrons. To calculate the probability that ionization will occur during these impacts, researchers use a quantity named the “ionization cross-section.” EII is among the main processes affecting the balance of charges in hot plasma, but so far, its cross-section has proven incredibly difficult to study through theoretical calculations.

Through new research published in The European Physical Journal D, Stefan Schippers and colleagues at Justus-Liebig University of Giessen, Germany, present new calculations for the EII cross-section, which closely match with their experimental results. Their discoveries could provide useful new insights in many fields of research where is studied, including astrophysics and controlled nuclear fusion.

So far, EII cross-sections have proven especially challenging to calculate for two key reasons: the that can emerge between the electrons involved in the process, and the wide array of possible electron configurations in the atoms being impacted.

How China’s Moon mission could reveal the origins of life on Earth

Update: China´s Moon Mission Returned Now Samples from the #Moon to #Earth. Why this is important, specially for the origin of life:

On June 1, China’s Chang’e-6 lander touched down in the South Pole-Atkin Basin — the largest, deepest, and oldest impact crater on the Moon. The probe almost immediately set to work drilling into the ground to collect about 2 kilograms of lunar material, which is already headed back to Earth, with a landing in Mongolia planned for June 25. It isn’t just planetary geologists who are excited at what the returning rocks and soil might reveal. If we’re lucky, the first samples from the lunar farside could also include some of the oldest fossils ever found.

The SPA basin, as it’s sometimes called, is the result of a gigantic impact that occurred between 4.2 and 4.3 billion years ago, at a time when the Moon and Earth were very close neighbors. The crater is roughly 2,500 kilometers (1,600 miles) in diameter and between 6.2 km and 8.2 km (3.9 to 5.1 mi) deep, encompassing several smaller craters like the Apollo basin, where Chang’e-6 landed, and Shackleton crater, parts of which lie in perpetual shadow.

The main focus of 21st-century lunar exploration is searching for natural resources such as water ice that could be turned into rocket fuel and drinking water for astronauts, as well as helium-3 that might someday fuel nuclear fusion reactors. Another potential scientific treasure is often overlooked, however. The Moon is the only place where we might find fossilized clues to the origin of life on Earth. On our own planet’s dynamic surface, hungry microbes would have destroyed such evidence a long time ago.

Why don’t electrons in the atom enter the nucleus?

Article 39 Why an electron does not fall into the nucleus in terms of the strong and weak nuclear forces.

Your thoughts would be appreciated.

It can be shown one may able to derive the strong and weak nuclear forces and the internal geometry of protons and neutrons in terms of the orientation of…

Electrons in the atom do enter the nucleus. In fact, electrons in the s states tend to peak at the nucleus. Electrons are not little balls that can fall into the nucleus under electrostatic attraction. Rather, electrons are quantized wavefunctions that spread out in space and can sometimes act like particles in limited ways. An electron in an atom spreads out according to its energy. The states with more energy are more spread out. All electron states overlap with the nucleus, so the concept of an electron “falling into” or “entering” the nucleus does not really make sense. Electrons are always partially in the nucleus.

If the question was supposed to ask, “Why don’t electrons in the atom get localized in the nucleus?” then the answer is still “they do”. Electrons can get localized in the nucleus, but it takes an interaction to make it happen. The process is known as “electron capture” and it is an important mode of radioactive decay. In electron capture, an atomic electron is absorbed by a proton in the nucleus, turning the proton into a neutron. The electron starts as a regular atomic electron, with its wavefunction spreading through the atom and overlapping with the nucleus. In time, the electron reacts with the proton via its overlapping portion, collapses to a point in the nucleus, and disappears as it becomes part of the new neutron. Because the atom now has one less proton, electron capture is a type of radioactive decay that turns one element into another element.

If the question was supposed to ask, “Why is it rare for electrons to get localized in the nucleus?” then the answer is: it takes an interaction in the nucleus to completely localize an electron there, and there is often nothing for the electron to interact with. An electron will only react with a proton in the nucleus via electron capture if there are too many protons in the nucleus. When there are too many protons, some of the outer protons are loosely bound and more free to react with the electron. But most atoms do not have too many protons, so there is nothing for the electron to interact with. As a result, each electron in a stable atom remains in its spread-out wavefunction shape. Each electron continues to flow in, out, and around the nucleus without finding anything in the nucleus to interact with that would collapse it down inside the nucleus.

Continue reading “Why don’t electrons in the atom enter the nucleus?” | >

The Universe’s Biggest Explosions made Elements we are Composed of, but there’s Another Mystery Source out there

After its “birth” in the Big Bang, the universe consisted mainly of hydrogen and a few helium atoms. These are the lightest elements in the periodic table. More-or-less all elements heavier than helium were produced in the 13.8 billion years between the Big Bang and the present day.

Stars have produced many of these heavier elements through the process of nuclear fusion. However, this only makes elements as heavy as iron. The creation of any heavier elements would consume energy instead of releasing it.

In order to explain the presence of these heavier elements today, it’s necessary to find phenomena that can produce them. One type of event that fits the bill is a gamma-ray burst (GRB)—the most powerful class of explosion in the universe. These can erupt with a quintillion (10 followed by 18 zeros) times the luminosity of our sun, and are thought to be caused by several types of event.

China reveals fusion tech breakthrough

A commercial ‘artificial sun’ has achieved its first plasma discharge, the developer says © Getty Images / mesh cube.

The Chinese privately run fusion company Energy Singularity has built the world’s first fully high-temperature superconducting tokamak, and used it to produce plasma, state media outlets have reported, citing the firm.

The creation of the device, dubbed HH70 and located in Shanghai, is seen as a major step in the development of fusion technology to potentially generate clean energy.

Neutrino mixer

Why are neutrinos so light?

Did you know that every second more than 100 trillion tiny particles called neutrinos pass through your body without causing any harm? These mysterious particles are produced abundantly throughout the universe in events like nuclear reactions in the sun, radioactive decays in the Earth’s crust, and in high-energy collisions in space. In particular, these subatomic particles play a crucial role in the explosive deaths of stars known as supernovae, where they act as the driving force behind the explosion. Despite their abundance in the universe, they are incredibly difficult to detect directly in experiments since they pass right through any matter and only interact extremely rarely. At the LHC, their existence can only be inferred indirectly by summing up the energy of all other particles produced from the proton collisions and looking for missing energy that has been carried away by the neutrino, which escaped the experiment undetected.

Neutrinos are a type of fundamental particle known as a lepton and they are electrically neutral. They stand out among fundamental particles because of their peculiar characteristics. Not only do they interact exceptionally rarely, but they also possess a minuscule mass, approximately 500,000 times lighter than that of an electron. One possible explanation for the smallness of their mass is given by the “seesaw” mechanism. According to this theory, there exist additional new fundamental particles that are electrically neutral. The mechanism postulates that the masses of these new particles, known as “heavy neutral leptons” (HNLs), are mathematically linked to those of the normal neutrinos, like two sides of a seesaw. The theory also predicts that the HNLs will “mix” with their known cousins, neutrinos. This means that a neutrino, produced in an LHC collision, can change into an HNL, and the HNL can then decay back into known particles that the LHC experiments can detect!

The seesaw explanation for the neutrino mass is particularly attractive and various searches for HNLs have been performed at the LHC and by other experiments in the past (see an example where CMS muon detectors are exploited in such a search). The CMS Collaboration has recently published a new search that makes the assumption that the mixing between the HNLs and neutrinos is very small. In this special case, the HNL can be “long lived” and travel macroscopic distances away from the collision point before decaying. Experiments can then take advantage of the unusual signatures from these “displaced” particle decays when trying to find evidence for the existence of HNLs.

‘Ghost Particles’ Could Be The Secret Behind The Heaviest Elements

Big atoms demand big energy to construct. A new model of quantum interactions now suggests some of the lightest particles in the Universe might play a critical role in how at least some heavy elements form.

Physicists in the US have shown how subatomic ‘ghost’ particles known as neutrinos could force atomic nuclei into becoming new elements.

Not only would this be an entirely different method for building elements heavier than iron, it could also describe a long-hypothesized ‘in-between’ path that sits on the border between two known processes, nuclear fusion and nucleosynthesis.

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