Ultraviolet sensitivity of a teledyne-e2v EMCCD

Quantum yield estimation for an electron-multiplying charge-coupled device from photon counting test data

“…We performed the analysis on 1000 images per wavelength taken with a mean electron multiplication gain of 1000 output electrons per input electron. The illumination was not the same between wavelengths, at a radiant flux of 3.06 × 10 4 photon∕s at 150 nm, 9.18 × 10 4 photon∕s at 165 nm, and 4.65 × 10 4 photon∕s at 180 nm 14 spread out over an ∼60 × 40 pixel region with exposure times of 1 s. Note that these are a factor of 2.04 × 10 −4 lower than those listed by Rowlands et al 14 due to a 100-μm pinhole placed in front of the 7-mm mask they used for their Table 1 Quantum yield results from simulated data. We quote both the "corrected" and "uncorrected" values, but we do not recommend using this correction method because of these results on the simulated data.…”

“…Our quantum yield measurements are consistently higher than those from the photon transfer method. In Table 3, we use the various quantum yield estimates from Table 2 and responsive quantum efficiency measurements by Rowlands et al 14 to estimate the IQE of the detector. The IQE should not be able to exceed unity minus the reflectance of bare silicon at that wavelength as that would imply that the surface is absorbing photons that should have been reflected at the surface.…”

“…Similarly, the Hubble Space Telescope's Wide Field Camera 3 is also uncoated silicon and Baggett 22 and Borders et al 23 found quantum yields up to 30% less than predicted. One possible solution that Rowlands et al 14 proposed is that the astro-no-coat process does not actively force photogenerated electrons away from the surface so it is more prone to charge trapping and recombination. This is not supported by the measurements of Scott et al 9 which show that the overall responsivity of the CIS113 CMOS detector is very similar to that measured on a NIST-calibrated uncoated silicon photodiode.…”

“…In this paper, we refer to this lower bound as the "silicon reflectance" quantum yield estimate. 14 The test was performed under vacuum in a cryostat, which had been baked out before testing, with a cold plate to account for residual offgassing. For more details on the setup, see block diagram in Fig.…”

“…Following on with the promising results obtained with the UV enhanced CIS113 sensor described above, we procured five EMCCD 201-20s from Teledyne-e2v, which were also processed as "astro-no-coat" for enhanced UV sensitivity (in the same manner as the CIS113). Initial UV performance was reported by Rowlands et al 14 using typical photon transfer methods. Additional UV photon-counting data were also collected and the analysis of these data is reported here.…”