Katie was the lab assistant of Ray Palmer, the Atom.
History
Katie helped Professor Palmer when he tried to repair a defective nanobot. Palmer told Katie he blamed her for the fault — on the grounds that, as a professor, he could not be blamed for it.
After successfully dealing with the problem, Katie interrupted Palmer's rest by stating he had company — serious company. Told by Superman that they had a "Omega-level situation", the Atom asked Katie to notify the front office of his impending absence.