Maturing electron multiplying charge coupled device photon-counting with variable multiplication gain imaging for a coronagraphic instrument

This is an introduction to a US government program that conducted high-contrast imaging experiments with an electron multiplying charge coupled device (EMCCD) in an interferometric coronagraph. This report will introduce the concepts of "charge blooming" and "starlight saturation" in the context of high-contrast astronomical imaging. These phenomena adversely effect the performance of high-contrast photon-counting instruments that do not use a mask to physically block starlight in the science channel of the coronagraph. The problems will be presented with the help of images taken with a commercial EMCCD camera in the visible nulling coronagraph at the Goddard Space Flight Center. A new clocking scheme for EMCCDs-variable multiplication gain clocking-will be proposed as a means for suppressing horizontal blooming and starlight saturation in an astronomical camera. This opening report will conclude with a discussion of design considerations for a new controller for high-contrast photon-counting with an EMCCD in a coronagraphic instrument. This controller will allow a single frame from an EMCCD to be scanned in multiple modes-photon-counting and digitization-with a variable multiplication gain clock to enable direct imaging of an exoplanet and wavefront control of a coronagraph, simultaneously.

[Design of Dyson Flow Cytometry System]

In order to meet the needs of the flow cytometry for the simultaneous analysis of multiple fluorescence wavelengths and small volume, the design method of flow cytometry spectrum analysis system is presented by analyzing the characteristics of Dyson structure. And according to the method, a flow cytometry spectrum analysis system is disigned with Dyson type.The system's spectral range is 400 nm to 800 nm, the defocused spot size is less than the pixel size 24μ mm, the ransfer function value is above 0.8 at the Nyquist cut-off frequency 21 lp/mm,the spectral resolution is less than 3 nm, and the overall size is 83.54 mm×85.60 mm.The system has good optical performance and small volume, which meets the needs of the flow cytometry fluorescence spectral analysis. The outstanding innovation of this system is the application of Dyson light splitting structure and EMCCD detector which is high speed and high sensitivity.