The largest lecture hall at Ångström Laboratory is Siegbahnsalen (Siegbahn hall). It holds 220 people and is located on ground floor in the middle of the building.

There is OH, computer projector, document camera, DVD-player, stationary mikes, headset mike, hand mikes, blackboards, whiteboards and stationary hearing loop in the hall.

Siegbahnsalen is named after Kai Siegbahn (1918-2007) who was a Professor of Experimental Physics at Uppsala University 1954-1984. In 1981 he received the Nobel Prize in Physics just like his father, Manne Siegbahn (1886-1978) did in 1924.