From a point of a signal-to-background ratio, phosphors are a key component of micro channel plate (MCP) based x-ray framing cameras. In an MCP based framing camera, x-ray signal is converted to electrons, gated, amplified, and converted back to optical signal on the phosphor. To operate x-ray framing cameras in a harsh neutron induced radiation background of the National Ignition Facility, cathodeluminescence efficiency of the phosphor is very important. To avoid MCP damage due to high voltage

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... breakdown, we have been operating phosphors below 3kV (acceleration field < 6 kV/mm). The signal-to-background ratio the camera can be significantly improved by increasing the phosphor potential to 10kV. We measured conversion efficiencies of standard phosphors at electron energies of 0.5 ~10 keV and assessed achievable performance of them with using a numerical model.