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FIFI LS SITR April 2009

FIFI LS SITR April 2009. Randolf Klein (UCB) ‏. Quick Summary. Schedule Issues. Blue Spectrometer We are making good progress , but not as much as originally hoped. The main efforts are focussed on characterizing the red spectrometer. Schedule Issues. Documentation

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FIFI LS SITR April 2009

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  1. FIFI LSSITRApril 2009 Randolf Klein (UCB)‏

  2. Quick Summary

  3. Schedule Issues • Blue Spectrometer • We are making good progress, but not as much as originally hoped. The main efforts are focussed on characterizing the red spectrometer.

  4. Schedule Issues • Documentation • Not much real progress, yet, but preparations to get the airworthiness efforts re-started are very promising. • A TIM on FIFI LS Airworthiness will be held at the MPE on June 2nd, 2009.

  5. FIFI LS Team F. Fumi - electronics design - 1FTE N. Geis – FP guider + operations - 0.1 FTE R. Hönle - detector design and testing – 0.5 FTE R. Klein – project scientist & S/W (UCB) – 0.75 FTE L. Looney - system & optics (UIUC) – 0.1 FTE K. Nishikida – EOOP S/W - 1 FTE A. Poglitsch – PI and interface for CREs – 0.1 FTE W. Raab - cryo-mechanical systems & optics – 0.5 FTE USRA contact: Murad Hamidouche

  6. Schedule

  7. Budget • EOOP: underspending as planning had some margin FIFI LS itself is funded by the MPE.

  8. Progress

  9. Progress Summary • Extensive Performance tests of the Red Spectrometer • Alignment verification • CO spectra to verify spectral resolution • 399 out 400 red detector pixels working • Blue detector is finished + two spare modules

  10. Alignment verification HD [N II] [O I] [C II] CO 14-13 [N II] The point spread function has been measured at 6 wavelengths and found to consistent with the optical design last November (from last SITR). There was one under-illuminated column before the re-alignment.

  11. Alignment verification • Before: Modules 5, 10, 15, 20, 25 (blue dots) got ~1/2 the light of the other modules (red squares). The data is not corrected for responsivity variations and thus the scatter. • After re-alignment, no obvious decrease on the pixels in the “rightmost” column of the slicer. Only pixel 25 looks a bit weak, but not weaker than pixel 3. Could just be detectors.

  12. Alignment verification The pixel positions are the same after the re-alignment. And the relative pixel positions do not change with wavelength. The measurements show that the alignment is repeatable and the spatial calibration is stable.

  13. Spectral Resolution • The spectral resolution of FIFI LS was measured with 6 CO lines through out the red spectrometer’s wavelength range (J=23->22 @113µm to J=14->13 @186µm) at a gas cell pressure of 1.2 mbar executed with ~1/4 pixel step size. • Due to the low line intensity, all 399 working pixels had to be stacked. We first took the same scans at ~20 mbar to derive accurate center positions on all pixels individually. • These center positions were used to shift the individual low-pressure profiles for the stacking.

  14. Spectral Resolution A broadened CO line at “high pressure” of 20mbar to get an exact wavelength calibration for each pixel. Lorentz Gauß R=λ/Δλ1/21241 1363

  15. Spectral Resolution "J=15->14", 173.631, 1.2 mbar Hardly broadened CO line at 1.2mbar all 399 pixels stacked together. The stacking was actually done by drizzling the individual signals on a 1/8 pixel grid. The result of this procedure is shown as blue line. The Lorentz/Gauß fits were done to the full set of individual, shifted data directly. LorentzGauß R=λ/Δλ1/216101560

  16. Spectral Resolution Another example for a low pressure CO line. "J=23->22", 113.458, 1.2 mbar LorentzGauß R=λ/Δλ1/2695 704

  17. Spectral Resolution Spectral resolution vs wavelength Prediction vs Measurements The red curve shows simple model: Rectangular (rather than the elliptical geometrical beam), flat illumination of grating with borders determined by geometrical diameters of collimated beam. The resulting LSF is convolved with square pixel and FWHM calculated. Diffraction effects give a larger illumination at longer wavelength thus a higher spectral resolutio and vice versa. R µm

  18. Blue Detector Blue detector is finished! 25 detector modules plus CREs + 2 spares

  19. FIFI LSEOOPExtended Observing Opportunity Program Allowing the US community to use FIFI LS as if it were a facility instrument.

  20. Progress • The main focus lies on the data reduction pipeline. • Currently, we are realizing the drizzle step and will test the pipeline on real data from the recent tests. • Next steps: • Interface to DCS and test data ingestion. • Refine observing modes • Define FIFI LS API so that SOFIA can schedule FIFI LS observation

  21. Data Reduction Pipeline

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