Scanner beam
From Tardis Wiki, the free Doctor Who reference
A scanner beam was a component of Dr Fendelman's time scanner. "Eustace" absorbed the energy released when the beam damaged the time fissure in Fetchborough.
At the Fourth Doctor's instruction, Adam Colby utilised the beam to confuse the Fendahl, allowing the Time Lord to take Eustace out of Fetch Priory. (TV: Image of the Fendahl)