Intro duc tio n to JEM/ SMIL ES K. Kikuchi and JEM/SMILES Mission - PowerPoint PPT Presentation

Intro duc tio n to JEM/ SMIL ES K. Kikuchi and JEM/SMILES Mission Team (JAXA & NiCT) JEM/SMILES • Atmospheric Submillimeter Observation from Space • 640- GHz SIS Receiver with 4- K Mechanical Cooler

Contents � Overview of J Overview of J EM/ SMILES EM/ SMILES - Mission Objectives � Results from Receiver System (EM) Test Results from Receiver System (EM) Test - System Noise Temperature and Gain - Sideband Separation - Linearity Test - Beam Test - Gas Cell Measurement

EM/ SMILES EM/ SMILES Overview of J Overview of J

JEM/SMILES � Superconductive Submillimeter- Wave Limb- Superconductive Submillimeter- Wave Limb- Emission Sounder designed to be aboard the Emission Sounder designed to be aboard the J J apanese Experiment Module (J apanese Experiment Module (J EM) on ISS EM) on ISS � Collaboration project of J Collaboration project of J AXA and NiCT AXA and NiCT Mission Objectives � Space Demonstration of Superconductive Mixer Space Demonstration of Superconductive Mixer and 4- K Mechanical Cooler for Submillimeter and 4- K Mechanical Cooler for Submillimeter Limb- Emission Sounding Limb- Emission Sounding � Global Observations of Atmospheric Trace Gases Global Observations of Atmospheric Trace Gases in the Stratosphere in the Stratosphere

JEM/SMILES Payload Structure Model Majo Major De r Design Paramete sign Parameters rs • RF : 640 GHz band • Spectral Coverage: 1200 MHz x 2 • Antenna: 40 cm x 20 cm • Weight: < 500 kg • Mission Life: 1 year

Mechanical Cooler and SIS Mixer � Mechanical Cooler Mechanical Cooler ・ 4 K Two- stage Stirling and J - T ・ Cooling Capacity: 20mW @ 4K, 200mW @ 20K, 20 K 1000mW @ 100K ・ Power Consumption: < 300 W 100 K ・ Mass: 90 kg IF port � SIS Mixer SIS Mixer ・ ・ RF: 640 GHz IF: 11- 13 GHz 500 µ m ・ J unction: Nb/ AlOx/ Nb, ~7 kA/ cm 2 ・ RF Matching: PCTJ with Integrated Circuit ・ Fabricated at Nobeyama GND

Submillimeter Limb-Emission Sounding and Global Observation • look in “limb” directions of various tangent heights • cover latitudes of 65 N to 38 S T r a j e c t o r y i n 2 4 H o u r s

Multi-species, High-sensitive Observation of Trace Gases J EM/ SMILES outputs the altitude distribution and its variation for trace gases. ”Retrieval” Simulated spectra at different tangent heights (LSB)

Development Schedule

Results from Receiver System Results from Receiver System (EM) Test (EM) Test

Block Diagram of JEM/SMILES SRX: Submillimeter Receiver

Major Specification of Receiver System (SRX) RF Frequency: RF Frequency: 624.32- 626.32 GHz (LSB) 624.32- 626.32 GHz (LSB) 649.12- 650.32 GHz (USB) 649.12- 650.32 GHz (USB) IF Frequency: IF Frequency: 11.0- 13.0 GHz (LSB) 11.0- 13.0 GHz (LSB) 11.8- 13.0 GHz (USB) 11.8- 13.0 GHz (USB) Noise Temperature: Noise Temperature: < 500 K (Goal) < 500 K (Goal) Image Rejection Ratio: Image Rejection Ratio: > 15 dB > 15 dB 65.6 ± 2 dB Gain: Gain: Overall: verall: 65.6 2 dB Deviation:< 2.5 dB Deviation:< 2.5 dB p- p p- p (Goal) (Goal) < ± 1 % Linearity: Linearity: < 1 % Stability: < ± 1 % Stability: 1 % (in 1 min.) (in 1 min.)

Optical Jig RF Input Plate IF output EM Test of Receiver System SRX (EM) test has been uly 2005 completed in J

Noise Temperature and Gain (1/2) Noise Temperature Gain Noise Temp. [K] Gain [dB] Gain Dev. [dB p-p ] 65.6 ± 2 Specification < 500 goal < 2.5 goal USB-ch 447 mean / 498 max. 62.6 mean 3.0 LSB-ch 477 mean / 519 max. 62.1 mean 2.3 • Gain level is adjustable • Measured at 4.11 K (4-K stage temperature)

Noise Temperature and Gain (2/2) Achieve a better matching SIS Mixer (EM) between SIS mixer and SIS HEMT HEMT amp. to reduce noise Device Amp. temperature and gain ripple. SIS Mixer (FM) SIS Impedance HEMT Device Transformer Amp. Gain char. of SIS Mixer With Transformer Without Transformer IN OUT (SIS)

Sideband Separation FSP: Frequency- Selective Polarizer: FSP: Frequency- Selective Polarizer: ・ Extremely low reflection - - - Low standing waves ・ Suitable for a fixed- frequency application LO Flat Mirror WG B Cold Sky WG (LG1) WG A Antenna WG (RG1) FSP Flat Mirror absorber SIS Mixer(R) Wire-Grid(CG1) SIS Mixer(T)

Linearity Test SRX (Gain G ) r ~ 0.1 T AOPT ATT Cryo- H stat ∆ T C ∆ V(T) = G(T) ∆ T V ( H ) ≡ − Lock-in Amp. NL 1 Reference V ( C ) = NL 0 for linear case > NL 0 for saturated case

Beam Test (1/2) CW Source S i g n a l P o r t A L P H AOPT: ) N B R B T I m SMI ( Amb. Temp. B a B g H e ( C P S RM5b T o RM5a ) r Optics t e 5 M R LG1 A RM5c SLO B RG 1 RM6 RM5d SMXr CM2r Horn CG1 CM2t COPT: CM1 SMXt Cooled Optics Horn Position Err. [mm] Tilt Err. [deg] AOPT ± 1.23 max. ± 0.36 max. Mechanical – Beam axis COPT ± 0.28 max. ± 0.28 max. Mechanical – Beam axis AOPT – COPT ± 1.51 max. ± 0.64 max Beam axis

Beam Test (2/2) “Beam Shift” between AOPT and COPT by 1 mm First Result ~5 % increase of beam efficiency • Mechanical alignment alone is not enough. Adjustment of beam axis between AOPT and COPT is essential. • Beam efficiency of ~90 % will be achievable in FM.

Gas Cell Measurement (1/2) k SRX Gas Cell x 1 x 0 Cold Termination Transmittance : T (x) ∫ x 1 = − T ( x ) exp( k ( x ' ) dx ' ) x

Gas Cell Measurement (2/2) USB • CH 2 F 2 , H 37 Cl, and CH 3 CN • Measured with AOS(BBM) LSB LSB

Conclusion � J EM/ SMILES mission is overviewed. � The performance of SRX (EM) almost meets the requirements of J EM/ SMILES specification. http:/ / smiles.tksc.jaxa.jp