Introduction to JEM/SMILES 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 JEM/SMILES Results from Receiver System (EM) Test - Mission Objectives Results from Receiver System (EM) Test 　　- System Noise Temperature and Gain - Sideband Separation - Linearity Test - Beam Test - Gas Cell Measurement

Overview of JEM/SMILES

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

JEM/SMILES Payload Major Design Parameters RF : 640 GHz band Structure Model Major Design Parameters 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 4 K 20 K 100 K Mechanical Cooler ・Two-stage Stirling and J-T 　　・Cooling Capacity: 20mW @4K, 200mW @20K, 1000mW @100K 　　・Power Consumption: <300 W 　　・Mass: 90 kg SIS Mixer 　　・RF: 640 GHz　 ・IF: 11-13 GHz 　　・Junction: Nb/AlOx/Nb, ~7 kA/cm2 　　・RF Matching: PCTJ with Integrated Circuit ・Fabricated at Nobeyama IF port GND 500 mm

Submillimeter Limb-Emission Sounding and Global Observation look in “limb” directions of various tangent heights cover latitudes of 65 N to 38 S Trajectory in 24 Hours

Multi-species, High-sensitive Observation of Trace Gases JEM/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 (EM) Test

Block Diagram of JEM/SMILES SRX: Submillimeter Receiver

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

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

Noise Temperature and Gain (1/2)   Noise Temp. [K] Gain [dB] Gain Dev. [dBp-p] Specification < 500 goal 65.6±2 < 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 between SIS mixer and HEMT amp. to reduce noise temperature and gain ripple. SIS Device Impedance Transformer HEMT Amp. SIS Mixer (EM) SIS Mixer (FM) With Transformer Without Transformer Gain char. of SIS Mixer IN (SIS) OUT

Sideband Separation FSP: Frequency-Selective Polarizer: ・Extremely low reflection --- Low standing waves ・Suitable for a fixed-frequency application

Linearity Test SRX (Gain G ) DV(T) = G(T) DT Lock-in Amp. T Cryo- AOPT stat AOPT SRX (Gain G ) DV(T) = G(T) DT Reference ATT r ~ 0.1 C H

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

Beam Test (2/2) Mechanical alignment alone is not enough. Adjustment “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) x0 x1 Cold Termination Gas Cell k SRX Transmittance : T(x)

Gas Cell Measurement (2/2) USB CH2F2, H37Cl, and CH3CN Measured with AOS(BBM) LSB LSB

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