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Status of 1.8 THz Channel TELIS (TErahertz and submm LImb Sounder)

Status of 1.8 THz Channel TELIS (TErahertz and submm LImb Sounder). by Nopporn Suttiwong, Remote Sensing Technology Institute, DLR Oberpfaffenhofen. Preliminary design of the 1.8 THz Channel. 1.8 THz Channel (DLR). Mixer: Hot Electron Bolometer (HEB) Diplexer for coupling in LO DSB mode

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Status of 1.8 THz Channel TELIS (TErahertz and submm LImb Sounder)

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  1. Status of 1.8 THz Channel TELIS (TErahertz and submm LImb Sounder) byNopporn Suttiwong,Remote Sensing Technology Institute, DLR Oberpfaffenhofen

  2. Preliminary design of the 1.8 THz Channel 1.8 THz Channel (DLR) • Mixer: Hot Electron Bolometer (HEB) • Diplexer for coupling in LO • DSB mode • LO: solid state LO technology • Digital autocorrelator spectrometer

  3. 1.8 THz channel in the filght module cryostat 1.8 THz Receiver : Diplexer Characterization at 4 K Diplexer Overview • MPI based Diplexer • Leakage is about 0.7% • Optimizing Adjustment on absolute power • Diplexer was characterized at 4K in the flight module cryostat. • LO Frequency : 1.8464 THz • The figure shows the comparison of the expected diplexer position and the real measurement. Maximum output power

  4. 1.8 THz Receiver : Diplexer Characterization at 4 K Comparison of NT spectrum and the calibrated spectrum measured from optimizing with HEB‘s current and the one optimized with absolute power • Diplexer was characterized at 4K in the flight module cryostat. • LO Frequency : 1.8464 THz • The figure shows the comparison of the expected diplexer position and the real measurement. Maximum output power

  5. Methanol Gascell 1.8 THz Receiver : Measurement Setup

  6. 1.8 THz Receiver : Stability of receiver • Integration time = 2 sec • ~25 minutes measurement • Cooler at 10 K • LO: 1832.034 GHz • Absolute power from ACS (926 channels) • Standard deviation ~ +/- 0.4%

  7. 1.8 THz Receiver : System Noise Temperature Spectrum Noise temperature spectrum(across 2 GHz bandwidth) • measured in DSBmode • LO was tuned at 1830.214 GHz • Absolute NT ~2100 K From measurement on 29.11.2007 D:\TELIS\Measurement_results\2007\2730_11_2007_MicrowindowTHzCH\29_11_2007\ck_uWindows_reproducibility\2_c\ACS\mea2

  8. 1.8 THz Receiver : Methanol Spectrum The methanol spectrum measured in DSB mode • Measure Sequence : H-G-C-A-… • LO was tuned to 1.8428 THz • Sample gas : methanol Cell length : 50 cm. Window material : PE

  9. Microwindow Selection for THz channel * IF = 5 GHz

  10. Thank you very much for your attention

  11. Atmosphere Remote Sensing Measurement Ph.D Work packages Recently Test TELIS instrument • Why DSB mode on the first flight ? • SSB filter causes the extra standing wave in the system • SSB filter generates the audio-frequency at 4K

  12. Microwindow Selection for THz channel * IF = 5 GHz

  13. TELIS instrument Cryogenic 1.8 THz Channel Ph.D Work packages Ph.D‘s Goal Overview 1.8 THz receiver : NT Measurement

  14. TELIS instrument Cryogenic 1.8 THz Channel Ph.D Work packages Ph.D‘s Goal Overview 1.8 THz Receiver : System Noise Temperature The NT measurement (solid state LO) The NT measurement (FIR laser)

  15. Atmosphere Atmosphere Recently Test Remote Sensing Measurement Ph.D Work packages TELIS instrument 1.8 THz channel Prerequirement Radiometric Tsys: <600 K (RAL) <400 K (SRON) <6000 K (DLR) Gain error: <1% Offset error: <1 K Baseline ripple: <0.1 K Spectral Resolution : <4 MHz Range : 2 GHz (SRON, DLR) 4 GHz (RAL) Accuracy : <2 MHz

  16. TELIS instrument Cryogenic 1.8 THz Channel Ph.D‘s Goal Overview Ph.D Work packages What to be achieved? Hardware : • Development of 1.8 THz Channel in Testing Cryostat • Transfer 1.8 THz channel to the TELIS’s flight module cryostat Software : • Software development for laboratory test • Software development (ground) for the post processing which will be used in campaign Scientific work: • Characterization of 1.8 THz Channel in Testing/Flight Module Cryostat • Characterization of the TELIS’s IF backend • IF chain • Digital autocorrelator spectrometer • Analysis the measurement data from the first campaign (Teresina, Brasil : Nov 2007) • Focus-> OH ; Satellite validation of MLS/Aura

  17. TELIS instrument Cryogenic 1.8 THz Channel Ph.D‘s Goal Overview Ph.D Work packages Cryogenic THz channel Window Signal Optical bench

  18. TELIS instrument Cryogenic 1.8 THz Channel Ph.D Work packages Ph.D‘s Goal Overview Cryogenic THz channel SSB filter Polarizer Polarizer

  19. TELIS instrument Cryogenic 1.8 THz Channel Ph.D Work packages Ph.D‘s Goal Overview Cryogenic THz channel SSB filter Imaging Mirror LO

  20. TELIS instrument Cryogenic 1.8 THz Channel Ph.D Work packages Ph.D‘s Goal Overview Cryogenic THz channel SSB filter Diplexer LO Imaging Mirror HEB fIF(USB) = fS-fLO or fIF(LSB) = fLO-fS

  21. TELIS instrument Cryogenic 1.8 THz Channel Ph.D‘s Goal Overview Ph.D Work packages What has been done? / What to do more?

  22. Flight module cryostat TELIS MIPAS-B Telescope, Optical Module Autocorrelator plate First Integration of TELIS with MIPAS (10- 21.04.2007): “TELIS side view” “TELIS with MIPAS”

  23. TV Test in Karlsruhe (10- 21.04.2007): “TELIS in Vacuum Chamber” Heat pipe and Black body Autocorrelator Plate Analog/Digital Racks

  24. Atmosphere Recently Test Remote Sensing Measurement Ph.D Work packages TELIS instrument Limb Sounding Measurement from balloon platform • Atmospheric profiles of molecular abundances, temperature, and pressure can be determined from the measured emission spectra.

  25. HEB,LO,Dip,SSB, Telescope, etc. Spectrum Post- Processing Raw Data PC104 DB TCP/IP Calibrated Spectra ACS Server Software Development: • Autocorrelator calibration • Spectral post-processing • Quantization correction • Calibrating the raw spectra Ground Balloon

  26. Atmosphere Atmosphere Recently Test Remote Sensing Measurement Ph.D Work packages TELIS instrument TELIS instrument’s specification Radiometric Tsys: <600 K (RAL) <400 K (SRON) <6000 K (DLR) Gain error: <1% Offset error: <1 K Baseline ripple: <0.1 K Spectral Resolution : <4 MHz Range : 2 GHz (SRON, DLR) 4 GHz (RAL) Accuracy : <2 MHz

  27. Testing cryostat Bolometer Atmosphere Remote Sensing Measurement Ph.D Work packages Recently Test TELIS instrument Stability of THz channel system The output power of LO (measured by Bolometer) A strong influence on the receiver stability comes from the LO source. The utilization of a solid state LO provides the better system stability of the THz channel. The coupling optics was carefully designed in order to provide sufficient LO power to drive the HEB mixer.

  28. Atmosphere Remote Sensing Measurement TELIS instrument Recently Test Ph.D Work packages What has been done? / What to do more?

  29. TELIS Team DLR Institut für Methodik der Fernerkundung PI, total system, 1.8 THz channel DLR Abteilung MORABA Microcontroller, consultancy DLR Institut für Planetenforschung HEB mixer for 1.8 THz channel RAL Rutherford Appleton Laboratories, U.K. 500 GHz channel, level 2 processing, cryostat design and fabrication Institut für Meteorologie und Klimaforschung Forschungszentrum Karlsruhe Gondola, consultancy Institut für Umweltphysik, Uni Bremen Consultancy SRON Space Research Organisation of the Netherlands 600 GHz channel, level 2 processing, optical design, HIFI technology Chalmers University of Technology, Sweden HEB mixer for 1.8 THz channel, level 2 processing Institut für Mikrowellentechnik Universität Bern, Switzerland Consultancy optical design, heterodyne receiver, antenna profiles, spectrometer

  30. TELIS instrument Cryogenic 1.8 THz Channel Ph.D‘s Goal Overview MIPAS gondola „with TELIS“ Ph.D Work packages TELIS instrument overview • Limb sounding technique • Balloon platform: height range 10-40 km, altitude resolution 2 km • TELIS consists of three channels: DLR : 1830 40 GHz SRON : 600 – 660GHz RAL : 499 – 503 GHz • MIPAS &TELIS on the same platform Speciesmeasured by TELIS DLR :OH, HO2,HCl,NO, NO2, O3, H2O, O2,HOCl RAL :BrO,ClO, O3, N2O SRON :ClO, BrO, O3,HCl, HOCl, H2O,HO2, NO, N2O, HNO3,CH3Cl, HCN, H218O,H217O,HDO TELIS highlights Sensitivity improved vs. MIPAS-B

  31. Cryogenic 1.8 THz Channel TELIS instrument Ph.D‘s Goal Overview Atmosphere Transferoptic Thermal Radiation Source LO generation Autocorrelator Spectrometer (4ch x 2GHz) IF chain (4-6GHz) Diplexer SSB filter DLR HEB mixer SSB filter SRON Integrated Receiver IF chain (5-7GHz) Rate Gyroscope Pointing motor /encoder SSB filter RAL SIS mixer IF chain 2x2-4GHz Cryostat LO generation PC104 Pointing Controller MIPAS Altitude and heading reference system House Keeping Unit (Temperature, Voltage) Balloon Ground Client Computer Server Computer Client Computer Telescope Ph.D Work packages TELIS instrument’s schematic diagram

  32. TELIS instrument Cryogenic 1.8 THz Channel Ph.D Work packages Ph.D‘s Goal Overview Cryogenic THz channel Mixer (HEB) Diplexer (MPI) SSB filter (MPI) LO Optical bench Cryostat Window

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