Junji Inatani and SMILES Mission Team (NASDA & CRL) EMC Design of SMILES Junji Inatani and SMILES Mission Team (NASDA & CRL) July 25, 2001 JEM-SMILES

Contents Introduction to SMILES Particular EMC Required for SMILES SMILES’ Strategy of EMC Design Experimental Results Conclusions July 25, 2001 JEM-SMILES

July 25, 2001 JEM-SMILES

Instruments SMILES: Superconducting Submillimeter-wave Limb-emission Sounder View in the Cryostat July 25, 2001 JEM-SMILES

Signal Flow July 25, 2001 JEM-SMILES

ISS Environmental Fields July 25, 2001 JEM-SMILES

EMC Requirement of SMILES All components shall work properly while SMILES meets the specified requirements CE, RE, CS, RS .......... SSP-30237 EMC at “malfunction” level RS (radiation susceptibility) is most critical for SMILES to achieve its designed sensitivity SMILES deals with atmospheric emissions at extremely low levels (completely passive sensor) EMC at “spurious emission” level EMC to deteriorate the linearity of detection July 25, 2001 JEM-SMILES

SMILES’ Strategy for EMC Design EM shielding with mainframe panels To protect ambient temperature components conductive seal, cutoff filter (venting holes) EMC with PIU (connections to JEM-EF) EM shielding with receiver cryostat To protect cryogenic temperature components conductive seal (metallic O-ring) low-pass filter for DC input leads EMC design in submillimeter optics Immunity of components to be improved To request control for 11-13 GHz emissions July 25, 2001 JEM-SMILES

Signal Level Diagram July 25, 2001 JEM-SMILES

SMILES Structural Model Antenna (REF) Antenna (TRN) Acoustic test was done to establish mechanical design. EM shielding performance was measured. Alignment Panel Star Trackers Calib. Hot Load July 25, 2001 JEM-SMILES

Shielding Effect of Mainframe Panels July 25, 2001 JEM-SMILES

Shielded Receiver Submm Optics (AOPT) Antenna Receiver Cryostat Bellows Back-to-back Horn (Cutoff Filter) SIS Mixer 4 K 20 K HEMT Amp. 100 K 300 K Receiver Cryostat July 25, 2001 JEM-SMILES

Ambient Temp. Optics (AOPT) To Antenna AOPT Cryostat To Cold-Sky Terminator AAMP Single Sideband Filter CREC Sub-mm LO Source He Compressor (JT) He Compressor (ST) July 25, 2001 JEM-SMILES

Cutoff Filter (Circular Waveguide) Mainframe/Venting Holes: D= 4.0 mm, L= 7.0 mm Optics/BBH (Signal): D= 8.650-5.905 mm (profiled), L= 132.243 mm Optics/BBH (Image): D= 5.905 mm (straight), L= 75.000 mm July 25, 2001 JEM-SMILES

AOPT (EM) Signal/Image Coupler SSB Filter LO/Image Coupler LO Source BBH (Image Port) BBH (Signal Port) July 25, 2001 JEM-SMILES

Reflection of BBH Return Loss > 50 dB RX BBH TX @ 625 GHz A. Murk, Univ. Bern R. Wylde, TK July 25, 2001 JEM-SMILES

Conclusions ISS Electro-magnetic environment is harmful to some type of experiments like SMILES. To cope with that, SMILES has adopted two-fold EM shielding techniques for its sensitive instruments. SMILES structural model has achieved the shielding performance above 20-30 dB. For SMILES to fully enjoy its sensitive observations, ISS environmental field has to be less than 2 V/m at 11-13 GHz. July 25, 2001 JEM-SMILES