Swensen

From Memory Alpha, the free Star Trek reference.

You may also be looking for science officer Swenson.

Swensen was a Starfleet security officer stationed on board the USS Enterprise during the 2260s.

In 2268, he, together with security officer Bardoli, was part of a landing party led by Captain Kirk that was searching for the dikironium cloud creature on Argus X. (TOS: "Obsession")

Later that year Swensen was called to the transporter room where kept his phaser trained on Jojo Krako when the latter beamed aboard the Enterprise. (TOS: "A Piece of the Action")

Swensen was played by an unknown actor.