1. An apparatus comprising:
a vapor cell having:
a first cavity configured to receive a first material;
a second cavity fluidly connected to the first cavity by a first channel, the second cavity configured to receive one or more
gases dissociated from the first material and allow radiation to pass through; and
a third cavity fluidly connected to one of the first cavity or the second cavity by a second channel, the third cavity configured
to receive a second material for absorbing a portion of the one or more gases dissociated from the first material.