Note: Effect of photodiode aluminum cathode frame on spectral sensitivity in the soft x-ray energy band

M.B. McGarry, P. Franz, D.J. Den Hartog, J.A. Goetz, J. Johnson

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Silicon photodiodes used for soft x-ray detection typically have a thin metal electrode partially covering the active area of the photodiode, which subtly alters the spectral sensitivity of the photodiode. As a specific example, AXUV4BST photodiodes from International Radiation Detectors have a 1.0 μm thick aluminum frame covering 19% of the active area of the photodiode, which attenuates the measured x-ray signal below ∼6 keV. This effect has a small systematic impact on the electron temperature calculated from measurements of soft x-ray bremsstrahlung emission from a high-temperature plasma. Although the systematic error introduced by the aluminum frame is only a few percent in typical experimental conditions on the Madison Symmetric Torus, it may be more significant for other instruments that use similar detectors.
Original languageEnglish
Article number096105
Pages (from-to)-
JournalReview of Scientific Instruments
Issue number9
Publication statusPublished - 1 Sep 2014
Externally publishedYes


All Science Journal Classification (ASJC) codes

  • Instrumentation

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