Which temperature sensor is rugged one and can measure high temperature?
This is the kind of thing that I do all day long. One area for you to examine is called fiber optic thermometry (or phosphor thermometry or fluoroptic thermometry.) Some fibers can be built to withstand as much as \$450\:^\circ\textrm{C}\$, and more if you have enough money. They are very resistant to chemical attack, as well, and can be built to use very narrow fibers or rather larger ones, as well. Typical operating temperature range will be from about \$-200\:^\circ\textrm{C}\$ to a little over \$300\:^\circ\textrm{C}\$. Your range fits squarely in there. Inexpensive precision will be on the order of a few tenths of a degree Celsius. Accuracy, about half a degree. These probes are used inside of power substation transformer cores, for one example category of use, which are filled with rather hot oil and the fibers need to last decades in that environment. They can be low power, as well. But you haven't specified that. (You also haven't said how often you need a measurement.)

I've even done this with sapphire light pipes, which can withstand quite a lot of abuse, chemical attack, and temperatures probably over \$1900\:^\circ\textrm{C}\$, when they do start to get near their melting point. But that was done in a combo sensor which used phosphor for temperatures up to about \$400\:^\circ\textrm{C}\$ and pyrometry methods (same sensor installed in a space shuttle heat shield) above that. That single sensor works from \$-200\:^\circ\textrm{C}\$ to a little over \$1900\:^\circ\textrm{C}\$ using the same instrumentation box. But you'll pay for such fancy capability.

Fluorescent thermometry like this can even work by painting a ceramic mixture on the surface of a jet engine blade and pulsing light onto it while it operates at full speed, making in situ measurements in places where you'd think there was no possible way to do it. It's pretty versatile and has its place.