From Halopedia, the Halo wiki
UNSC Naval Intelligence
R. Carmi is Tech Specialist 6 at Chawla Base, specializing in magnetometer's. She worked for Major Standish in one of the buildings 40-44 (likely Building 41) as the lead tech studying the Deep-Space Artifact .
In an audio clip created by the Operator to sneak information to Durga, "Rani Sobeck" says that Carmi went on maternity leave. "Herzog" then denies this, saying she disappeared. Whether either of these are true is uncertain.