Optimization of thin-foil based phosphor screens for CCD imaging in TEM in the voltage range of 80–400 kV

The voltage dependence characteristics of thin-foil based phosphor screens in the thickness range of ∼ 10–60 μm are examined for CCD imaging in transmission electron microscopy (TEM) in the voltage range of 80–400 kV. The brightest screen is obtained with a P20 layer of about 12 μm at 80 kV, and a thicker screen lowers both the screen brightness and resolution. The thickness of the brightest screen is higher at higher voltages, but other considerations for a practical CCD imaging system suggest that the P20 layer should not be greater than ∼ 18 μm for the voltage range stated above.