020116EIS_JTM.1 EIS Sensitivity Update John Mariska NRL 3-5 Feb 2003

020116EIS_JTM.2 EIS Effective Areas First set of flight optics coated at Columbia University and Characterized at Brookhaven Effective areas computed using –Measured M 1 reflectivities –Measured FL 7 efficiencies (combination of reflectivity and groove efficiency) –Same Al filter transmission as earlier calculations –Al filter mesh transmission factor of 0.85 –Spider transmission factor of 0.80 –CCD QE of 0.80 –Mirror area of 0.5*88.4 Results are near those used in all earlier EIS sensitivity calculations

020116EIS_JTM.3 EIS Effective Area Curves

020116EIS_JTM.4 EIS Effective Area Data All data files used to compute the effective area are in the EIS SolarSoft directory $SSW_EIS/response –All data files are text, with #-delimited comments at beginning –Read using data = rd_tfile(file, /nocom, /auto, /conv) –Each data file has a three digit extension—higher numbers are newer, so highest number of each file should be considered current Key files are –EIS_EffArea_A.001 and EIS_EffArea_B.001 –Procedure for reading effective area files will be placed in $SSW_EIS/idl/cal and will default to taking highest version number of area files –Procedures for using emission measure curves and Chianti data to generate spectra for planning purposes under development

020116EIS_JTM.5 Modeling EIS Using preliminary sensitivity information, have modeled EIS detectors Model uses a TRACE 195 Angstrom image to interpolate between quiet Sun and active region differential emission measure curves For each location in the TRACE image, model computes an emission measure and uses that to synthesize the spectrum along the EIS slit Thermal, nonthermal, and instrumental broadening included Includes Poisson statistics on number of arriving photons and converts to photoelectrons and then DN Adds a pedestal—currently 100 electrons—and a normal distribution of read noise with a standard deviation of 6 electrons Will be updating to include random Doppler shifts and other delights Data and detailed description at

020116EIS_JTM.6 EIS Model Sample Output

020116EIS_JTM.7 EIS Model Implications Large difference in count rates between the two detectors For active regions and a 10 s integration, the model predicts –10,000 to 14,000 DN for Fe XII –1,500 DN for Fe XV Observing strategy will need to carefully consider how to handle these differences