To provide cooling apparatus for cooling a workpiece or sensor down to the region of the melting point of helium where it is not necessary to pre-cool the inside of the apparatus using liquid nitrogen etc. The remote controller transmits a remote control code in accordance with an output of the switch and an output of the item selector. Based on the corrected representative condition, color conversion conditions corresponding to two or more medium types that belong to the same group as the representative type are corrected collectively. Ceramic particles made by the method are part of the invention. A method for producing a sodium niobate powder includes a step of holding an aqueous alkali dispersion liquid containing a niobium component and a sodium component at a pressure exceeding 0.