Cryogenic cooling without helium gas

Can be used for superconducting refrigerant, cell freezing, and semiconductor cleaning

Overview

　Helium is difficult to obtain and expensive, so cooling systems that use helium are expected to be difficult to continue using. 　 The invention enables rapid cooling without helium by continuously spraying a two-phase flow of cryogenic gaseous N₂ and solid N₂ (SN₂ ). Specifically, it is characterized by continuously generating slush N₂ by spraying at transonic speed using a Laval nozzle.
　In an example of cell freezing, a 23% improvement in cell survival rate during thawing was achieved compared to liquid nitrogen immersion. This invention has the potential for application in various cooling systems beyond this specific example. Additionally, its application for resist removal in semiconductor cleaning without harmful chemicals is also under consideration.

Cooling characteristics by SN₂ particulate spray

Product Application

・Superconducting refrigerant　
・Semiconductor refrigerant
・Rapid freezing of food and cells
・Semiconductor cleaning (resist removing)

Related Works

[1] TEION KOGAKU (J. Cryo. Soc. Jpn.) Vol.42 No.5 (2007)
[2] TEION KOGAKU (J. Cryo. Soc. Jpn.) Vol.44 No.2 (2009)
[3] Jun Ishimoto et al 2014 ECS J. Solid State Sci. Technol. 3 N3046 DOI 10.1149/2.009401jss

IP Data

IP No.　 ： JP4961551, JP5419000, JP6153110, JP6573363
Inventor ： ISHIMOTO Jun
keyword ： refrigerant, freezing, refrigeration, superconductivity, nitrogen, N₂, helium alternative