Characterization of an X-ray framing camera utilizing a charge coupled device or film as recording media

A compact charge coupled device (CCD) camera system has been designed and c haracterized for use in the six inch manipulator (SIM) at the Nova laser fa cility. The camera system has been designed to directly replace the 35 mm f ilm packages currently used in SIM-based x-ray imaging diagnostics. The uni t's electronic package has been constructed for small size and high thermal conductivity which reduces the overall camera size and improves its perfor mance when operated within the vacuum environment of the Nova target chambe r. Measurements of the x-ray imager's contrast transfer function (CTF) were made under a variety of operating conditions on a static x-ray Manson sour ce using both the CCD and Kodak T-Max 3200 film as recording media. The CTF data were converted to an equivalent modulation transfer function (MTF). T he MTF plots show that the microchannel plate has a uniform response within our measurement accuracy along its strips. In a direction normal to the st rip, however, the MTF is reduced due to the slant angle of the pores in the MCP. The measurements show that the CCD camera has a lower MTF response th an T-MAX film for all spatial frequencies and configurations measured. Howe ver, data obtained from the film exhibited reciprocity failure and border e ffects that are not observed in the CCD data. Measurements indicate that th e signal-to-noise ratio for the CCD data is four to six times larger than t hat obtained with film and higher photon flux levels were recorded. The CCD -based diagnostic offers immediate access to the data, improved dynamic ran ge, and reduced turnaround time, while eliminating the need for film develo pment, digitization, equipment, and personnel. (C) 1998 American Institute of Physics. [S0034-6748(98)00912-5].