Not so much a 'proper' Chamber, more of a series of small puzzles as you navigate more of the outside of the science centre.
Go through the force field to your right and then look to your left of the walkway for a shoot-able section of wall. Position a portal here and now turn to your left and look up for the word 'GAMMA' painted in white on a wall. Get your next portal up here, step on through, past the force field and onto the next series of puzzles.
There’s a control room located on the opposite side of the room, so make your way down here, hit all three switches and then go back to the entrance of this room.
Jump off the walkway onto the blue gel below, this’ll bounce you up to the ledge opposite. You’re now on the upper level of the room and it’ll be coated in loads of orange propulsion gel. Watch out for the compressors and time your dash past them so they’re rising as you pass under them.
At the end of the room, open the door to your right, look for the slanted portion of wall outside on your right and then place an exit portal here. Go back inside, and zoom down the corridor towards the wall at the other end.
Walk through the test subject waiting area and when you drop down a level, go into the right-hand room and press the red switch on the wall. Head back out and around, step outside and follow the walkway to the elevator and the end of this particular challenge.