Question

What was the sensitive, well-insulated tool Willard F. Libby used to date artifacts with known ages?

Answer 1

Willard F. Libby used Geiger Müller tubes to date artifacts with known ages. 

Answer 2

Willard Frank Libby used to date artifacts with known ages, "Geiger-Muller tubes". At this time, the chemistry professors and students of Berkeley were developing an interest in atomic energy. So, as a senior project Libby set to work building a highly sensitive "Geiger-Müller tube" that could be used by the department to test the radioactivity of various elements. Hope this helps you. Thanks!

-Charlie