Experimental characterisation of CCD cameras for HREM at 300 kV

摘要

The modulation transfer function, noise transfer function and detection quantum efficiency of both 1k~2 and 2k~2 cameras attached to the same 300 kV FEGTEM have been measured. The results show that both the MTF and the DQE of the 2k~2 camera are lower than for the 1k~2 camera at frequencies above a third of the Nyquist limit. This lower per-pixel performance of the 2k~2 camera is primarily a result of the use of a thicker phosphor scintillator. However, MTF and DQE of the 2k~2 camera operated as an effective lk~2 camera by using 2 x 2 pixel binning are superior to the 1k~2 camera in the medium spatial frequency range.