Figure 3.

Figure 3: Comparison of QE for CCDs optimized for the near-UV (200-400nm). The figure shows the ACS High Resolution Camera (HRC) processed by Mike Lesser, the ACS flight backup CCD incorporating the SITe "UV-AR" process, the STIS backside process and the WFPC2 frontside CCD which coated with a phosphor. Note that the QEs for the three thinned CCDs have not been corrected for quantum yield. The WFPC2 CCD detects UV photons at ~500 nm, the wavelength at which they are down-converted"