Vacuum-ultraviolet quantum efficiency of a phosphor-coated charge-coupled device
Applied Optics
|October 2, 2010
Summary
We measured the quantum efficiency (QE) of two phosphor-coated charge-coupled devices. Average QE was approximately 18% between 1600-3800 Å, with a read noise of 8 electrons.
Area of Science:
- Astrophysics
- Instrumentation
Background:
- Charge-coupled devices (CCDs) are crucial for astronomical observations.
- Phosphor coatings enhance UV sensitivity but require careful characterization.
Purpose of the Study:
- To determine the absolute quantum efficiency (QE) of two phosphor-coated CCD detectors.
- To assess the spatial uniformity and read noise of these devices.
Main Methods:
- Absolute QE measurements were performed on two 1024x1024 pixel CCDs.
- Measurements covered the wavelength band from 1216 to 5200 Å.
- Spatial uniformity and read noise were also evaluated.
Main Results:
- Average QE was 17.7 ± 1.8% (lot 1) and 18.1 ± 1.8% (lot 2) in the 1600–3800 Å band.
- Sensitivity reached 32% at 5200 Å and decreased below 1600 Å.
- Read noise was measured at 8 electrons; spatial uniformity was ±2% at 5200 Å.
Conclusions:
- The tested CCDs demonstrate moderate QE in the UV and visible spectrum.
- Detector uniformity varies, with one device showing a flat UV response.
- These detectors are suitable for applications requiring low read noise and specific wavelength sensitivity.
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