Tokyo Tech News

Plasma pioneers


Published: November 30, 2010

The details of research

Tokyo Institute of Technology group launch venture company to commercialize multi-gas atmospheric plasma sources

A new company called ‘Plasma Concept Tokyo Ltd' has been launched by Tokyo Institute of Technology researchers. Akitoshi Okino and colleagues in the Department of Energy Sciences hope to commercialize the results of their research into new-types of atmospheric plasma sources, which have potential applications including surface treatment, semiconductor processing, surgery, safe disposal of harmful gases, spectroscopic analysis, and sterilization of food and agricultural products.

Plasma is often referred to as the fourth state of matter in which ions, electrons, neutral particles and radicals move randomly. The highly reactive radicals in plasmas are used for sterilization, deodorization and etching semiconductors. In addition, the optical properties of plasmas are exploited in plasma displays, lasers and emission spectrometry, and the high temperature of plasmas - over 5,000 °c - is exploited for burning refuse, welding materials and finally, nuclear fusion. Notably, the methods used for producing plasmas depend on the desired properties of the resulting plasma — pressure, temperature, purity and type of gas.

Okino and co-workers are focused on the production and applications of multi-gas, stable, atmospheric plasma, which has many advantages over other kinds of plasmas. For example, it can be produced inexpensively using simple equipment without any need to produce vacuums. The researchers can also achieve continuous processing by putting the sample directly into the plasma and without the need for differential pumping mechanisms. Finally, the high density of atmospheric plasma means that this processing can be done at high speeds.

An intriguing application of this group's technology is the decomposition of the anesthetic gas nitrous oxide (N2O), otherwise known as laughing gas. This gas is widely used during surgery, but as a result vast amounts of it are released into the atmosphere where it accelerates global warming. According to data compiled by Okino, approximately 1000 tons of N2O are used during surgery in Japan each year and, given that N2O is a particularly powerful greenhouse gas, this has the equivalent effect of 300,000 tons of carbon dioxide.

As a solution to this problem, Okino and colleagues developed a system for producing a plasma directly using N2O itself. Their new technology thereby enables the highly efficient and low cost dissociation of this harmful gas. This is just one of the exciting real-world applications that the Tokyo Institute of Technology venture ‘Plasma Concept Tokyo Ltd' plans to commercialize.

Further information

Fig. 1: The direct dissociation of ‘laughing gas' producing atmospheric plasma.

Fig. 1: The direct dissociation of ‘laughing gas' producing atmospheric plasma.

Fig. 2: Damage-free multi-gas plasma jet.

Akitoshi Okino
Graduate School of Interdisciplinary Science and Engineering Energy Sciences
Associate Professor