1. November 13, 2003COS Preship Review1 Resolution Specification Definition of resolution –In all cases the resolution is defined as , where  is the FWHM of an emission line measured in pixels multiplied by the dispersion determined during wavelength calibration. –The FWHM of the line is determined by collapsing the line the cross dispersion direction and fitting a gaussian to the line profile.

2. November 13, 2003COS Preship Review2 G130 Resolution FUV resolution measured as part of Test 1110 Qualitatively speaking, those lines with very low or very high spectral resolution tend to have few counts. Bright lines generally exceed spectral resolution requirements.

3. November 13, 2003COS Preship Review3 G160 Resolution FUV resolution measured as part of Test 1110

4. November 13, 2003COS Preship Review4 G140 Resolution FUV resolution measured as part of Test 1110

5. November 13, 2003COS Preship Review5 NUV Wavelength Coverage Individual wavelength settings for the NUV channel cover non-contiguous parts of the full NUV spectrum. Multiple grating settings are required to sample the full wavelength coverage of each NUV grating. Point of note

6. November 13, 2003COS Preship Review6 G185M Resolution G185M resolution –Measured during Appendix B, Tests 1160 & 1155 –Initial results from Test 1160 found lower than expected resolution. This was attributed to misalignment between RAS/Cal & COS –Resolution tests repeated in GN2 environment during Test 1155 at ambient thermal environment existed. –Resolution meets specifications over measured band-pass. Shorter wavelengths could not be observed in GN2 environment. –G185M band-pass is from 1670-2127Å. 80% of this band-pass is 1760-2127. Symbols refer to OSM2 wavelength settings Multiple settings are required to cover entire band-pass 80% ?

7. November 13, 2003COS Preship Review7 G225M resolution –Measured during Appendix B, Tests 1170 & 1156 –Initial results from Test 1170 found lower than expected resolution. This was attributed to misalignment between RAS/Cal & COS –Resolution tests repeated in GN2 environment during Test 1156 at ambient thermal environment existed. –Resolution meets specifications G225M Resolution Symbols refer to OSM2 wavelength settings Multiple settings are required to cover entire band-pass

8. November 13, 2003COS Preship Review8 G285M resolution –Measured during Test 1180 –Resolution meets specifications G285M Resolution Symbols refer to OSM2 wavelength settings Multiple settings are required to cover entire bandp-pass

9. November 13, 2003COS Preship Review9 G230L resolution –Measured during test 1190 –Resolution meets specifications over most of the band-pass –Band-pass is 1700-3200Å. 80% is 2000-3200Å. G230L Resolution 80%

10. November 13, 2003COS Preship Review10 FUV02 meets QE specifications (UCB memo COS-021217-JV). Visible light rejection is 1x10 -12 and 4x10 -11 (ref. UCB memo COS-031027- JBM). Absolute efficiency measurements are based on a calibrated photodiode, so the absolute error ~10%. FUV Detector Requirements

11. November 13, 2003COS Preship Review11 Digitized pixel size is described in UCB memo COS-031027-JBM. Pixel sizes in final data are 6x24 microns. Dispersion and cross- dispersion resolution are shown to the right and discussed in UCB memo COS-031027-JBM. Detector x-resolution for segment A does impact net spectral resolution. FUV Detector Requirements

12. November 13, 2003COS Preship Review12 XDL dark rate measured during to be ~0.425 counts/sec/cm 2 (UCB memo COS-031027-JBM), exceeding the 0.5 counts/sec/cm 2 specification. XDL maximum global and local rate discussed in UCB memos COS- 031027-JBM, COS-010807-JV, and COS-010404-JVV. Requirements are met. FUV Detector Requirements

13. November 13, 2003COS Preship Review13 Evaluation of the FUV flat field is progressing. The histograms to the right show the distribution of pixel-to-pixel variations in the p- flats for segment A & B. (FUV detector meets flat field uniformity specification) Stability of the flat field with charge extraction is under investigation. Quick look analysis showed no appreciable difference in the PHD after the deep flat fields were acquired. This is an ongoing investigation. FUV Detector Requirements FUV Flat Field Data

14. November 13, 2003COS Preship Review14 FUV Detector Requirements Specification listed in CEI corresponds to <100%/C/cm 2, the rate of change of the modal gain with charge extraction, assuming the DRM. FUV02 MCPs were scrubbed to <100%/C/cm 2, so they meet the specification. Results and test description can be found in UCB memos COS-031027- JBM and COS-991208-JV.

15. November 13, 2003COS Preship Review15 FUV Detector Requirements Results presented in UCB memos COS-031027-JBM and UCB-COS- RPT-1164 Rev A. Focal plane matching meets requirements.

16. November 13, 2003COS Preship Review16 NUV Detector Requirements Results from Test 2170 –O2 absorption spectrum –Final spectrum consists of multiple individual spectra that were cross-correlated and co-added. –Individual spectra consisted of multiple FP-Split exposures –Data were flat fielded as well. –SN in the continuum exceeds 100.

17. November 13, 2003COS Preship Review17 Per COS-NUV-001, the lifetime requirement placed on the NUV detector when it was built is “10% DQE loss at >8x10 10 counts/mm 2 ”. –This specification corresponds to 5x10 7 counts/pixel –The NUV channel uses 3 stripes, each 3x1024 pixels = 9216 total pixels –This means that the NUV detector will suffer a 10% loss in DQE when it has observed 4.6x10 11 events TOTAL in the 3 spectral stripes. –The DRM (COS ISR 99-01) states that the NUV channel can expect to see 1.4x10 9 counts over the lifetime of the mission. –This is 2 orders of magnitude below the value at which the NUV detector will experience a 10% loss of DQE. –Finally, the three spectral stripes for each channel do not fall on the same region of the detector, thus increasing the number of pixels used and decreasing the net counts/pixel. –It is reasonable to assume that the NUV lifetime will support the lifetime requirements. The re-entrant window in the NUV channel was polished to < /4 at 6328Å as stated in the certification logs. –The re-entrant window defines the focal surface of the detector. /4 = 158 nm << 0.1 mm, thus the NUV detector focal plane meets requirements. NUV Detector Requirements

18. November 13, 2003COS Preship Review18 GSFC IVT verified the alignment of CAOS and RAS/Cal prior to each major alignment or test activity. No reports describing the alignment have been issued by the IVT at this time. Optical Stimulus Requirements

19. November 13, 2003COS Preship Review19 COS Wavelength Coverage

20. November 13, 2003COS Preship Review20 COS Wavelength Coverage FUV NUV COS wavelength scales extend across required wavelengths

21. November 13, 2003COS Preship Review21 Accuracy Requirement - NUV NUV Accuracy Data from wavecals that accompanied external Pt-Ne tests 1160, 1170, 1180. The measured stripe B central wavelength was within … –± 5 resels 68% –± 10 resels 88% –± 15 resels 100%.

22. November 13, 2003COS Preship Review22 Repeatability Requirement - NUV Comparison of repeated visits to same setup position. 107 spectra in 14 groups (grating, setup , FPSPLIT). Cross-correlation using 1 spectrum as reference. 3 stripes averaged. Assume 1 resel = 3 NUV pixels. Repeatability is ± 1 resel 77% of cases ± 6 resels 100%. NUV Repeatability

23. November 13, 2003COS Preship Review23 Accuracy Requirement - UFV 5 supported OSM1 setup positions Each allows 4 FPSPLIT offsets of 1 mechanism step each Measured wavelengths are within required range FUV Accuracy

24. November 13, 2003COS Preship Review24 Repeatability Requirement - FUV FUV Repeatability Comparison of repeated visits to same setup position. 47 spectra in 11 groups (grating, setup , FPSPLIT). Cross-correlation using 1 spectrum as reference. Seg A & B averaged. Assume 1 resel = 6 FUV pixels. Repeatability is… –± 1 resel 39% of cases –± 6 resels 100%.

25. November 13, 2003COS Preship Review25 850 Repeatability Test Test # 850 was developed and run as a repeatability monitor Test was run four times during Appendix B phase. The same exposures are included in the System Functional Test, and will be obtained each time the FT is run.

26. November 13, 2003COS Preship Review26 850 Repeatability Test FUV, G160M, Seg B wavecal centroids 1  ~4 pixels FWHM 1  ~0.4 pixels brightness 1  ~ 2% Analysis by Scott Friedman

27. November 13, 2003COS Preship Review27 850 Repeatability Test NUV, G185M, Stripe B wavecal centroids 1  ~3.5 pixels FWHM 1  ~0.2 pixels brightness 1  ~ 3% Analysis by Scott Friedman

28. November 13, 2003COS Preship Review28 Wavelength Scale Requirements This requirement addresses two issues –That the residuals in the wavelength calibration are << 15 km/s –That applying the wavelength calibration as determined from the wavelength calibration spectrum with an appropriate offset in the a 0 term of the wavelength solution to the science spectrum does not introduce error greater than 15 km/sec in the absolute wavelength scale (1 resolution element). –1 NUV pixel = ~4 km/sec Residuals in wavelength scale meet requirements. G285 - C Stripe, cen=2850Å

29. November 13, 2003COS Preship Review29 FUV Wavelength Scale Residuals Residuals are <3 FUV pixels (~6 km/sec) rms=1.2 pixels rms=0.8 pixels

30. November 13, 2003COS Preship Review30 Errors in offset wavelength calibration Applying an internal (WCA) wavelength solution to external (PSA) data (45 lines) yields an average error of… -0.26 ± 1.12 pixels, or -0.04 ± 0.19 spectral resels.

31. November 13, 2003COS Preship Review31 G130M Efficiency Efficiency measured at more than 5 wavelengths for all FUV and NUV channels. Appendix A test 400, July 05 Appendix B test 1210, Oct 11

32. November 13, 2003COS Preship Review32 G160M Efficiency Appendix A test 400, July 05 Appendix B test 1220, Oct 11

33. November 13, 2003COS Preship Review33 G140L Efficiency Appendix A test 400, July 05 Appendix B test 1230, Oct 11 This point falls outside the specified wavelength range and thus does not violate requirements.

34. November 13, 2003COS Preship Review34 G185M Efficiency Appendix A test 450, July 03 Appendix B test 1250, Sept 22 Appendix B test 1255, Sept 24 Note: The new CEI values for the NUV channels are values that have been submitted as a change request, NOT a waiver. These new values were rederived after an over-sight made early in the development of COS was discovered. Basically, when the NUV channel was broken into three channels from two the CEI values were copied not rederived. No prior knowledge of the as-built component efficiencies was assumed. 6 of 8 of the values actually increased compared to current values in CEI.

35. November 13, 2003COS Preship Review35 G225M Efficiency Appendix A test 450, July 03 Appendix A test 450, July 05 Appendix B test 1260, Sept 21 Appendix B test 1255, Sept 24 The procedure for monitoring the stability of the G225M grating is written and is being routed for signatures (COS-05- 0004). Note that G185M channel can be used to observe the short wavelength portion of the G225M band-pass with higher efficiency.

36. November 13, 2003COS Preship Review36 G285M Efficiency Appendix A test 450, July 03 Appendix A test 450, July 05 Appendix B test 1270, Sept 21

37. November 13, 2003COS Preship Review37 G230L Efficiency Appendix A test 450, July 03 Appendix B test 1280, Sept 22

38. November 13, 2003COS Preship Review38 BOA Transmission BOA Transmission measured during Tests 3310, 3310A, and 3300. The BOA is ~ND2.5 Meets requirements

39. November 13, 2003COS Preship Review39 G185M –2 nd order band-pass lies completely below 1150Å Al/MgF 2 cut-off G225M –No order sorter: 2 nd order efficiency was predicted to be very low due to low reflectivity of coatings [a] –Only grating where 2 nd order efficiency was measured –2 nd order efficiency measured during test 1265. –G225M, = 1248 (no order sorter) detected in m=2 with efficiency = 0.0004. = 2487 detected in m=1 with efficiency = 0.03. Ratio = 0.013. G285M & G230L –2 nd order measured, but not fully analyzed –G285M, G230L (with order sorters) did not detect = 1248. Upper limit of efficiency = 1.2x10 -5. Out of Band Response ChannelBandpass2 nd orderOrder sorter G185M1700-2127850-1064No G225M2070-25271035-1264No a G285M2480-32291240-1614Yes G230L1700-3200850-1600Yes TA11700-3200NAYes TA1BRT1700-3200NANo b TA1 –FUV efficiency measured during test 1290. –Efficiencies were almost unmeasureable due to two passes through the order sorter TA1BRT –FUV efficiency measured during test 1295 –Efficiencies higher than for TA1 due to 5% front surface reflectivity [b]

40. November 13, 2003COS Preship Review40 NUV Spatial Imaging NUV performance measured during Test 2250 and Test 150 10 pixels = 250  m

41. November 13, 2003COS Preship Review41 FUV Spatial Resolution G160M performance measured during Test 2731 7x7 pinhole array 338 um (1”) spacing in spatial dimension 100 um in spectral dimension 10 pixels = 240  m

42. November 13, 2003COS Preship Review42 FUV Signal to Noise Requirements Data taken at the component level has been used to demonstrate the ability to achieve SN>100. Data taken during Tests 1700 and 3000 (flat field spectra taken with onboard D2 lamps) and Test 2120 (CO absorption spectra). –G130M used to derive flat field for FUV segment A –G160M used to derive flat field for FUV segment B –Absorption spectra sufficient to demonstrate SN~70. The test was cut short due to the detection of ~10% drop in the flux from the onboard D2 lamps. –Can easily meet 30:1 requirement –Evaluation of component level flat field data suggests we can achieve 100:1 –Analysis of data acquired during final calibration is ongoing.

43. November 13, 2003COS Preship Review43 FUV Flat Field Data The achieved signal to noise under different assumptions We are actively working on developing the p-flats necessary to increase the signal to noise further.

44. November 13, 2003COS Preship Review44 Component Level Results The next few slides summarizes a an analysis conducted for FUV02 based on component level flat fields that demonstrates we can expect to achieve SN 100:1. The data set presented was taken prior to delivery of FUV02 and after the final scrub of the MCP stack was completed. –~29 hours of data were taken, or about ~1x10 9 events/segment. All data was taken as event lists. 108 files were processed. –No special environmental conditions were imposed on the test, so the temperature of the detector and electronics varied several degrees during the data acquisition. –For this analysis the data were thermally corrected and then the data was divided into two halves (image 1 and image 2). –Image 1 was then divided by image 2 and the statistics of the residuals were analyzed to evaluate the stability and noise characteristics of the flat field images. –In addition, FPSPLITs observations - the nominal observing mode - was simulated by shifting and adding 4 copies the same spectrum. The residuals were then evaluated and an effective signal to noise computed.

45. November 13, 2003COS Preship Review45 Images of Segment A A portion of the two flat field images of segment A (7000<x pixel <9400). Image 1 is divided into Image 2 to evaluate our ability to flat field segment A. Image 1 Image 2 Component Level Results

46. November 13, 2003COS Preship Review46 Component Level Testing Flat Fielded Images for A This images is the result of dividing image 1 by image 2 for segment A. Segment A Note the lack of structure evident in the residuals.

47. November 13, 2003COS Preship Review47 Component Level Testing Description of the Data Products Histogram of the ratio of image 1 to image 2 for the full image between x pixels 7000 and 9400. Histogram of the ratio of image 1 to image 2 for the spectral region. Note: The fact that the two histograms are identical in width suggests that noise is identical for the full detector image and extracted region. Histogram of the ratio of image 1 to image 2 for the spectral region per 6x12 pixel resolution element (RE). The width of the distribution is smaller because there are more counts per spectral bin compared to the counts per image bin. Spectral region Dispersion Direction Cross-dispersion Direction ~250  m high

48. November 13, 2003COS Preship Review48 Component Level Testing Histogram of Flat Field - A Left is the histogram for the full detector. Right is the histogram for the spectral stripe only. Each plot is extracted from the divided image shown earlier. The computed SN (45:1) is consistent with our expectations based on the error analysis of dividing two images. Conclusion: We are able to flat field the FUV data to the limit of photon statistics.

49. November 13, 2003COS Preship Review49 Component Level Testing Simulated FPSPLITS - A Effective photon limited SN ~ 126 per image. The measured SN~91 is consistent with the back of the envelope prediction of SN~89. The computed signal to noise is consistent with the gains expected by averaging 4 data sets. This indicates that the current plan for reducing the fixed pattern noise through standard FPSPLIT observations will work. = + + +

50. November 13, 2003COS Preship Review50 NUV Signal to Noise Requirements All flat field data acquired using G185M mode. NUV flat field data taken during Tests 1750, 2505, 1750 & 2506. High quality O 2 absorption spectra taken during Test 2170. –Data from 2170 demonstrates SN>100. –Data acquired using G185M, cen =1817Å. Demonstration of SN>100:1 means that we can meet all 30:1 requirements. All NUV SN requirements met.

51. November 13, 2003COS Preship Review51 NUV Flat Field Data The achieved signal to noise under different assumptions. Bottom line is that we essentially achieve photon limited signal noise.

52. November 13, 2003COS Preship Review52 NUV O 2 Absorption Spectra

53. November 13, 2003COS Preship Review53 Vignetting Requirement TA1 image of a fully illuminated aperture with a Kr lamp. 1”=42 pixels 167 pixels = 4” –This is extended field of view as predicted by ray-trace modeling. –Non-uniform illumination is a result of lamp filament or vignetting prior to PSA. 167 pix

54. November 13, 2003COS Preship Review54 Scattered Light Requirement Residual intensity due to scattered light was measured during Tests 2160 and 2110 Measured scattered light for G185M is ~0.5% Measured scattered light for G130M, G160M, and G140L are all <1%

55. November 13, 2003COS Preship Review55 Drift/Jitter Requirements Drift Correction Figure at the far left shows the x-centroid of an isolated FUV emission line over a 6000 second observation. The panel in the middle shows the corrected x-centroid. To do the correction the 6000 second observation was divided into 120 sec. Each sub-exposure was cross-correlated against the first sub-exposure and an offset computed. The time dependent offset was then applied to the data, thus correcting the drift to better than 0.7 pixels (0.12 resolution elements). 35 /s

56. November 13, 2003COS Preship Review56 Measurement of Jitter Evaluation of Jitter –Jitter in the dispersion direction will broaden an emission line and raise the mean, decreasing the spectral resolution. –Using the data set shown on the previous slide, the width of a bright emission line was computed every 10 seconds. –The computed FWHM is shown in the upper right. Note how the width is centered about 5.5 pixels. –The figure in the lower right shows the distribution of the x FWHM with a 1  of 0.77 pixels. An FUV resolution element is ~6 pixels, so the measured 2  jitter for time scales > 10 seconds is about 0.25 resolution elements. –The width of the resolution curve is likely dominated by statistical fluctuations, in which case the jitter is even smaller.

57. November 13, 2003COS Preship Review57 NUV Imaging Capability - bandpass Light for TA1 passes through fused-silica order sorter twice. Throughput = 6x10 -5 cts/ph at 1524, undetectable at 1248. Light for TA1-BRT reflects off of front surface of fused silica. It is not attenuated by absorption. Throughput = 2x10 -3 cts/ph at 1524, 8x10 -4 at 1248.

58. November 13, 2003COS Preship Review58 NUV Imaging Capability Data acquired during Appendix A, Test 150 Spots are separated by ~42 pixels, exactly as predicted by ray-trace models. Target acquisition algorithms, software, and NUV optical design support knowledge of target location in the PSA to <0.1” 42 pixels = 1.0” (280  m at PSA)

59. November 13, 2003COS Preship Review59 Target Acquisition Target Acquisition software includes 5 phases –Spiral search –Aperture location calibration –Image mode acquisition –Peakup in the cross-dispersion direction –Peakup in the dispersion direction Each phase of TA and associated parameters were tested during 11 tests in Appendix B.

60. November 13, 2003COS Preship Review60 Target Acquisition No software errors – code functions properly Data needed to establish software parameters were obtained All phases of TA were exercised All algorithms were used, produced consistent results All required hardware modes were used (and a few that are unlikely ie TA1 + BOA) All directions of slews as expected – sign conventions All magnitudes within several pixels of expected Test results have established confidence in the target acquisition capability

61. November 13, 2003COS Preship Review61 Full reduction of the data products is proceeding with a target completion data of February 1, 2003. The data files and corresponding data products will be presented in AV-04.

62. November 13, 2003COS Preship Review62 Exposure Time 1.Each detector produces time tag events consisting of a dispersion and cross dispersion direction. See COS-UCB-001 (FUV ICD) and COS-NUV-001 (NUV performance document). 2.See FUV ICD COS-UCB-001 3.See UCB memo COS-010807-JV 4.See BATC report COS-NUV-001 1 2 3 4

63. November 13, 2003COS Preship Review63 Exposure Time Item 1:Verified in COS CS DIB Component Test, section 8.6 (FSW Requirement. 5.11) Items 2-7: Verified in COS CS DIB & DIB component test, section 8.3. Item 4: Exposure times between 0.1 through to 6500 seconds all verified. 1 2 3 4 5 6 7 8

64. November 13, 2003COS Preship Review64 Onboard Calibration 1.There is nothing in the design of COS that precludes this requirement. An external shutter optically isolates COS, so that calibration lamps can operate without compromising other SI operations. 2.Data shall be included in AV-04. The tests listed above were completed, so the data does exist. 3.The wavelength solutions presented earlier demonstrate that we meet this requirement. Complete wavelength solutions shall be included in AV-04. 4.The ability to correlate mechanism position versus wavelength is satisfied by the fact that the mechanism position is reported in the COS telemetry. 5.Signal to noise data and efficiency data presented earlier demonstrates that this requirement is satisfied. 2 3 1 4 5

65. November 13, 2003COS Preship Review65 Onboard Calibration This requirement is satisfied by the COS Target Acquisition SUDF and associated component level tests. The functionality of the target acquisition software was verified during Appendix B testing, Tests 1450, 1460, and 1470. Final data will be provided in AV-04.

66. November 13, 2003COS Preship Review66 Onboard Calibration The above plots show the accumulated flat field data and locations of the science stripes.

67. November 13, 2003COS Preship Review67 Onboard Calibration

68. November 13, 2003COS Preship Review68 Modes of Operation These requirements are satisfied as witnessed by this presentation. AV-04 (SI Pre-Launch Calibration Data) will serve as the final document demonstrating that these requirements are satisfied. “Functional and diagnostic tests” are verified the the CS FSW Requirements Document and associated traceability and verification matrices.

69. November 13, 2003COS Preship Review69 Bright Object Protection The detectors are only capable of producing x,y event streams (time tag). Acquisition of an accumulated image is provided by the CS DIB & DIB. There is no requirement that either detector alone acquire an image, only that COS instrument support this mode of operation. –Verified in CS DIB & DIB Component Level Tests Acquisition of data within sub-arrays is also provided by the DIB. –Verified in CS DIB & DIB Component Level Tests Protection against global and/or local over-light conditions is provided by the DCE, CS DCE, MCE, and CS MCE FSE. Verification is documented in the respective Component Level Tests.