A low‐energy‐electron‐diffraction (LEED) apparatus for investigation of physically adsorbed gases at low temperatures is described. A flat 75‐mm‐diam channel‐electron‐multiplier plate with phosphor screen permits high resolution operation of low incident beam current densities. The sample holder can be cooled by flowing helium gas and tilted for observation of the specular beam. Preliminary observations of krypton adsorbed on the basal plane of graphite are presented, including evidence for the transition from a monolayer in registry to a compressed monolayer.