1. SOFIE Spectral Response Mark Hervig, GATS Inc. Drivers: Filter Response Preceding Optics Detector Response Solar Source Out-of-band performance is critical Requirement: Out of band exoatmospheric solar energy < 1% of total signal Spectral performance is analyzed using total response based on predicted and measured characteristics of the optical elements and detectors. The optical layout is shown on the following page. For example, the total response (TR) for band 14 is TR 14 = R 17  T 19  R 13  T 14  DR 14 where R is reflection, T is transmission, DR is detector response, and subscript indicates optical element number. Below “actual” means that the filter transmissions are measurements from real filters. In the case of “actual” total response a number of other optical elements could be based on predictions.

2. SOFIE CSM layout

3. Notes and Definitions Half-power points (HPP) are the wavelengths where the filter bandpass transmission is 50% of the peak transmission value. The HPP on the short wavelength side of the bandpass is known as the cuton wavelength, or lower HPP (LHPP). The HPP on the long wavelength side is known as the cutoff wavelength, or upper HPP (UHPP). The bandpass is generally defined as the wavelength region between cuton and cutoff. Bandpass center is defined as the average of cuton and cutoff wavelengths Bandpass (filter) width is given in percent as: 200*(cutoff-cuton)/(cutoff+cuton). For the out-of-band (OOB) analysis, the in-band region was defined as the wavelength region 3 filter widths wide centered on the band center wavelength

4. Filter Part and Data list, bands 1-4 BandPart #Bandpass Data Angle / temperature Out-of-band Data Angle / temperature / wavelength (  m) Comment 114?14? 15°/ 260K No part # 223?23? 15°/ 260K No part # 324?24? 15°/ 260K No part # 414?14? 15°/ 260K 15°/ 260K / 0.7-2.0No part # Underlined bandpass data were used the in following OOB analysis Amb = ambient temperature (? K) *part received by SDL

5. Filter Part and Data list, bands 5 - 8 BandPart #Bandpass Data Angle / temperature Out-of-band Data Angle / temperature / wavelength (  m) Comment 51313 15°/ 260K 61212 71212 81212 Underlined bandpass data were used the in following OOB analysis Amb = ambient temperature (? K) *part received by SDL

6. Filter Part and Data list, bands 9-12 BandPart #Bandpass Data Angle / temperature Out-of-band Data Angle / temperature / wavelength (  m) Comment 91212 15°/ 260K 10 111(wit) 2* 3* 4 5 6 ? 0°/ amb, 15°/ 260K, 15°/amb 0°/ amb 15°/ 260K/ 2.0–3.32 15°/ 260K/ 1.0–2.0, 15°/ 260K/ 3.42–5.5No part # 127* 8 9 10* 11(wit) ? 0°/ amb 0°/ 260K, 15°/ 260K, 15°/amb 15°/ 260K/ 1.0–2.0, 15°/ 260K/ 2.0–3.44, 15°/ 260K/ 3.54–6.0No part # Underlined bandpass data were used the in the following analysis Amb = ambient temperature (? K) *part received by SDL

7. Filter Part and Data list, bands 13-16 BandPart #Bandpass Data Angle / temperature Out-of-band Data Angle / temperature / wavelength range (  m) Comment 131 2* 3 4* 5 wit ? 0°/ amb, 15°/ 260K, 15°/200K 0°/ amb 15°/ 260K, 15°/ 200K 15°/ 260K/ 1.0–2.0, 15°/ 260K/ 2.0–4.2, 15°/ 260K/ 4.6–6.0 No part # 142* 3* 5 15°/ 260K, 15°/ amb 15°/ 260K/ 2.0–3.26, 15°/ 260K/ 4.79–6.0no OOB 3.3-cuton 152 3* 5* ? 15°/ 260K, 15°/ amb 0°/ amb 15°/ amb/ 1.0–2.0, 15°/ 260K/ 2.0-4.85, 15°/ 260K/ 5.24-6.0No part # 162* 3* 5 Wit 0°/ amb 15°/ 260K 0°/ amb, 15°/ amb, 15°/ 260K15°/ 260K/ 1.0-3.0, 15°/ 260K/ 3.0-6.0 No part # Underlined bandpass data were used the in following analysis Amb = ambient temperature (? K) *part received by SDL

8. SOFIE Bandpass Performance BandMeasurement Center (  m) spec / actual filter Width (%) spec / actual filter Cuton – Cutoff (  m) spec / actual filter Cuton – Cutoff (cm -1 ) spec / actual filter 1O 3 strong0.290 / 0.2922.9 / 4.10.2857-0.2941 / 0.285- 0.29834000-35000 / 33605 – 35033 2O 3 weak0.328 / 0.3273.3 / 4.20.3226-0.3333 / 0.320– 0.33330000-31000 / 29988 - 31274 3particle strong0.862 / 0.8643.4 / 3.70.8475-0.8772 / 0.848- 0.88011400-11800 / 11363 - 11786 4particle weak1.03 / 1.034.4 / 4.31.0101-1.0526 / 1.009-1.0549500-9900 / 9487-9908 5H 2 O weak2.45 / 2.462.0 / 2.22.427-2.475 / 2.432 - 2.4864040-4120 / 4022- 4111 6H 2 O strong2.60 / 2.612.1 / 2.02.577-2.632 / 2.587 - 2.6403800-3880 / 3787 - 3865 7CO 2 strong2.77 / 2.782.0 / 2.12.740-2.749 / 2.750 - 2.8093580-3650 / 3560 - 3636 8CO 2 weak2.94 / 2.942.1 / 2.02.907-2.967 / 2.910 - 2.9703370-3440 / 3366 - 3435 9particle strong3.06 / 3.072.0 / 2.03.030-3.091 / 3.037 - 3.0983235-3300 / 3228 - 3292 10particle weak3.19 / 3.192.1 / 2.23.160-3.226 / 3.150 - 3.2203100-3165 / 3106 - 3174 11CH 4 strong3.37 / 3.382.2 / 2.33.333-3.401 / 3.341 - 3.4182940-3000 / 2926 - 2993 12CH 4 weak3.51 / 3.492.1 / 2.03.472-3.546 / 3.454 - 3.5232820-2880 / 2838 - 2894 13CO 2 strong4.35 / 4.364.3 / 4.84.255-4.444 / 4.257 - 4.4652250-2350 / 2239 - 2348 14CO 2 weak4.68 / 4.662.3 / 2.84.630-4.740 / 4.592 - 4.7212110-2160 / 2118 - 2177 15NO weak4.98 / 5.022.0 / 1.94.951-5.051 / 4.976 - 5.0691980-2020 / 1972 - 2009 16NO strong5.32 / 5.342.1 / 3.1 5.263-5.376 / 5.259 - 5.4221860-1900 / 1844 - 1901 All values based on total response curves, not just filter transmission curves. Filter width is defined from the  half-power points (cuton to cutoff). Band center is the average of the cuton and cutoff wavelengths.

9. SOFIE Bandpass Performance BandMeasurementFilter Transmission (%) Average in-band spec / predicted / actual Detector Response (%) Average in-band actual (part #) Total Response (%) Average in-band predicted / actual filter Out of Band Solar Energy (%) (Spec is < 1%) predicted / actual filter 1O 3 strong>80 / 95.2 / 43.987.6 (G07)17.6 / 14.90.020 / 2.837 2O 3 weak>80 / 93.4 / 64.452.1 (G07)9.0 / 14.90.326 / 0.024 3particle strong>80 / 97.7 / 83.923.8 (J540)5.1 / 4.40.029 / 0.123 4particle weak>80 / 98.4 / 80.838.6 (J550)20.1 / 16.80.449 / 0.008 5H 2 O weak>80 / 92.9 / 78.051.2 (J562)34.8 / 26.60.118 / 0.019 6H 2 O strong>80 / 93.0 / 72.448.9 (J541)32.2 / 25.80.152 / 0.047 7CO 2 strong>80 / 93.0 / 73.460.0 (J554)41.6 / 29.30.010 / 0.102 8CO 2 weak>80 / 93.0 / 68.359.8 (J553)41.3 / 31.40.028 / 0.388 9particle strong>80 / 92.9 / 67.062.3 (J559)44.4 / 28.00.002 / 0.053 10particle weak>80 / 93.0 / 66.466.3 (J561)42.9 / 30.40.013 / 0.107 11CH 4 strong>80 / 93.0 / 77.370.3 (J560)46.3 / 40.40.009 / 0.025 12CH 4 weak>80 / 93.0 / 75.178.7 (J552)53.1 / 45.10.078 / 0.092 13CO 2 strong>75 / 94.0 / 77.090.8 (J546)60.9 / 48.00.178 / 0.021 14CO 2 weak>75 / 92.7 / 69.996.8 (J544)66.0 / 51.60.118 / 0.008 15NO weak>75 / 92.3 / 68.998.5 (J542)66.6 / 51.20.173 / 0.310 16NO strong>75 / 92.6 / 70.878.5 (J547)54.3 / 40.10.250 / 1.178 Total response includes all preceding optical elements & detector response

10. Band 1 analysis

11. Band 2 analysis

12. Band 3 analysis

13. Band 4 analysis

14. Band 5 Analysis Notes:

15. Band 6 Analysis

16. Band 7 Analysis

17. Band 8 Analysis

18. Band 9 Analysis

19. Band 10 Analysis

20. Band 11: part to part consistency Shown are the filter transmissions for individual parts, all measured at 0 deg angle of incidence and ambient temperature.

21. Band 11 Analysis Notes: Filter location shift

22. Band 12: part to part consistency Shown are the filter transmissions for individual parts, all measured at 0 deg angle of incidence and ambient temperature.

23. Band 12 Analysis Notes: Filter location shift

24. CH4 channel (bands 11 & 12), filters & gas spectra

25. Band 13: part to part consistency Shown are the filter transmissions for individual parts, all measured at 0 deg angle of incidence and ambient temperature.

26. Band 13 Analysis

27. Band 14 Analysis Notes: Missing OOB data from 3.3 microns to cuton. Filter location shift

28. CO2 channel (bands 13 & 14), filters & gas spectra

29. Band 15 Analysis Notes: Filter location shift

30. Band 16 Analysis Notes: Filter location shift, broader

31. NO channel (bands 15 & 16), filters & gas spectra

32. Extra slides follow

33. Silicon Carbide Detectors, Bands 1 & 2  Ozone measurements originally used UV-enhanced silicon detectors The spectral response of UV-Si detectors is less than ideal: UV-Si response combined with solar spectrum = amplified out-of-band energy Can be addressed with stacked filters, difficult to verify, questionable stability  A new option: Silicon Carbide (SiC) detectors Ideal spectral response  twice as rad-hard as Si Space flight heritage Eliminates 2 nd filter  Bands 1 & 2 now use SiC solar source  detector response

34. Band 1 Spectral Response with SiC detector Predictions indicate excellent performance using silicon carbide detector Solar out-of-band = 0.02%

35. Backup slides follow

36. SOFIE Out of Band Performance As hardware arrives at SDL, the measured characteristics are used to predict performance and ensure that all parts meet our requirements. Requirement: Out of band exoatmospheric solar energy < 1% of total signal BandMeasurement Center (  m) Out of Band Solar Energy (%), Predicted Out of Band Solar Energy (%), Actual Filter & Detector 1O 3 strong0.2900.020 2O 3 weak0.3280.326 3particle strong0.8620.449 4particle weak1.030.016 5H 2 O weak2.450.1250.015 6H 2 O strong2.600.1670.046 7CO 2 strong2.770.2600.088 8CO 2 weak2.940.2360.336 9particle strong3.060.0030.042 10particle weak3.190.015 11CH 4 strong3.370.0120.020 12CH 4 weak3.510.1160.093 13CO 2 strong4.250.1770.014 14CO 2 weak4.630.1230.008 15NO weak4.980.1790.199 16NO strong5.320.2560.693 Here, in-band is defined as a region 3 filter widths wide centered on the band center wavelength

37. SOFIE Bandpass Performance, Continued BandMeasurementFilter Transmission (%) Average in-band spec / predicted or actual Detector Response (%) Average in-band predicted or actual (part #) Total Response (%) Average in-band predicted or actual filter 1O 3 strong>80 / 95.287.639.3 2O 3 weak>80 / 93.429.417.8 3particle strong>80 / 97.723.8 (J540)21.0 4particle weak>80 / 98.438.6 (J550)33.2 5H 2 O weak>80 / 86.851.2 (J562)37.2 6H 2 O strong>80 / 93.048.9 (J541)43.2 7CO 2 strong>80 / 93.060.0 (J554)46.8 8CO 2 weak>80 / 93.059.8 (J553)48.5 9particle strong>80 / 92.962.3 (J559)71.2 10particle weak>80 / 93.066.3 (J561)66.7 11CH 4 strong>80 / 86.870.3 (J560)46.4 12CH 4 weak>80 / 84.278.7 (J552)49.0 13CO 2 strong>75 / 84.690.8 (J546)64.0 14CO 2 weak>75 / 78.696.8 (J544)64.6 15NO weak>75 / 79.198.5 (J542)63.1 16NO strong>75 / 80.678.5 (J547)50.4 In-band is wavelengths between the  half-power points Total response includes all preceding optical elements & detector response