Achievement of periodic table of elements (I)

The biggest pride of GSI Scientific Research Center (Germany) is the nuclear scientists here, on its UNILAC heavy ion accelerator, within 30 years, has successfully synthesized and been international Recognized as the inventors of the six superheavy elements never before known.

The search for new elements is fascinating scientific research, attracting special and widespread attention of the scientific community.

The path to the GSI Science Center

The appeal of unexplored unknowns


All chemical elements are formed in explosions billions of years ago in the universe, and it is these components of the physical world that make up stars, Earth and everything around us. , including the human body.

The collection of centuries-old research data shows that: Most elements in the periodic table of elements (THNT), from the lightest element such as Hydro (symbol H with atomic number Z = 1) to heavy most like Uranium (symbol U with Z = 92), are present on the earth. Because these are durable elements or very large life times, greater than our Earth's age.

But the heavier elements Uranium, called super uranium, especially the super-heavy elements far away from the table's uranium are unstable and decay very quickly. If millions of years ago, they were born with the formation of the Earth, but very little, or too short in life, compared to Earth's age, hundreds of thousands of years back (!), Time This is hard to leave a trace on Earth.

Therefore, most super-heavy elements are artificial, made in the laboratory in very small numbers, sometimes only counted on the fingertips. Although they are artificial, they will become rare evidences to answer the unknowns of the table, contributing to shedding light on the mysteries of the formation of the natural world, from small objects such as elementary particles, beads. big people like the Earth, the stars .

Machines of invention

Super heavy elements are formed by the following nuclear reaction: Shoot a 'bullet' particle; usually light particles such as neutron (n), proton (p) or other light nuclei into stationary 'beer' nuclei. The product obtained from this reaction is a new synthetic nucleus from two particles - bullets and beer - mentioned above.

Researchers have the task of selecting an optimal combination of bullets and beer particles in order to obtain the desired synthetic nuclei. In the experiments of super-heavy nuclear synthesis, the accelerator accelerated to help these bullets achieve a certain speed enough to overcome the barrier (Coulomb repulsion created by p particles carrying positive electricity in two particles bullet - beer) to be able to stick together to form a synthetic nucleus.

In the case of making super heavy elements from element 100, Fermium with Z = 100 and earlier, nuclear reactions occur by beaming neutrons (n) into Uranium beer and the phenomenon of capturing neutrons (n ) occurs, along with the process of beta particle decay (e) many times. The machine here is a source of neutron radiation, a nuclear reactor, even an atomic bomb explosion.

For the following Fermi elements (super Fermium elements), bullets are charged particles, usually ionic particles (ie atoms that have removed some electrons in the outer shell) of the central elements. Heavy, heavy or very heavy vessels are accelerated in the electromagnetic field of a large accelerator.

Thus, the large accelerator is the most important machine that is indispensable and super heavy elements can only form and detect in laboratories with sophisticated accelerators and analyzers, But it is so expensive that only a few developed countries have investment conditions. At the forefront of this field is the Berckley National Laboratory (USA) with HILAC Cyclotron accelerator (after upgrading to superHILAC), the Nuclear Reaction Chamber of the Dupna Science Center (the former Soviet Union) with the machines U-300, U-400 acceleration, is a heavy ion Cyclotron accelerator at RIKEN (Japan).

The machine of UNILAC invention

In GSI alone, to synthesize nuclei from 107 to 112, German scientists used the UNILAC (Universal Linear Accelerator) accelerator. This machine can accelerate the ions of the lightest elements - Hydro (proton), to the heaviest - Uranium with an energy of 11.4 MeV per unit of mass u, equivalent to the particle size of size 10. % the speed of light.

Accelerators are the main engine, but scientific success cannot be achieved without sophisticated and modern equipment other than the purpose of generating ion (ion source), separating products made by mass. and charge, that is, to accurately identify the newly formed elements. In GSI it is a gas-filled separators and a SHIP (velocity filter).

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