Chalk River BF3 Proportional Counter (ca. 1960s, 70s)

This neutron detector came from Chalk River Laboratories where it was probably used in cosmic ray investigations. It is 28 inches long, 2 1/2 inches in diameter, copper walled and filled with BF₃. Each end has a cap to protect the fragile glass insulators. The insulator shown to the right has a now sealed extension that was used to evacuate the tube and refill it with BF₃.

Donated by Chalk River Laboratories.