A connector mechanism for safely and quickly attaching or detaching a sensor. The connector mechanism includes a sensor head assembly comprising a detector body with an internal channel, an open distal end, and a sensor head attachment connector (HAC) located within the channel. The HAC includes a first electrical connection having at least a first contact member and a first key component located in a fixed location relative to the first contact member. The connector mechanism includes a sensor cartridge comprising a cartridge housing with a probe component, a second electrical connection having at least a second contact member configured to mate with the first contact member, and a second key component that is located in a fixed location relative to the second contact member. The first and second key components engage one another before the first and second contact members engage one another.