This was measured using deeply exposed flat-fields and taking a cut across each image. There was some uneveness in the illumination but the pixel to pixel sensitivity variations are clearly visible. At 390nm a cross hatch pattern with a spatial period of about 350 pixels is visible. If the chips were illuminated at 950nm with a collimated source, fringes with an amplitude of 13 % were also visible.

Mosaic CCD 1 :-

390nm.
 

565nm.
 

950nm

Mosaic CCD 2 :-

390nm.
 

 
565nm.

 
950nm