development of the next generation of multichroic sinuous...
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Load Resistors/BolometersFrom
Antenna
Development of the Next Generation of Multichroic Sinuous Antenna Coupled Transition Edge Sensor Detectors for CMB Polarimetry
B. Westbrook1, K. Arnold2, A. Cukierman1, W.L. Holzapfel1, A. T. Lee1, C. Raum,1 A. Suzuki1
1) University of California, Berkeley 2) University of California, San Diego
• Selfsimilar sinuous design is scaled to match the frequency range of interest• Tuning allows for the simultaneous observation of the Cosmic Microwave Background
(CMB) and cosmic foregrounds • Can tune to match atmospheric transmission windows for ground based observatories
• On chip banddefining filters separate the radiation into components • Currently we have tuned 7 bands with centers ranging between 30380 GHz• Requires broadband AR coatings and direct contact dielectric lenslets
• Oliver Jeong's Poster G4.13 (AR) • Praween Siritanasak's Poster G3.9 (lenslets)
• Multiplexing provides efficient use of focal plane area• Requires increased readout bandwidth and multiplexing factor
• Kaja Rotermund' Poster G2.45 (LC resonators)• Kaori Hattori's Talk (POLARBEAR 2 Readout Electronics)
Optical Characterization
Overview
A beam map from the Low Frequency Triplexer pixel at 90 GHz.
A beam map from the High Frequency Triplexer pixel at 220 GHz.
Technology
Spectral Bands & Science
Filter Design
The bands are defined by microstrip lumpedelement 3pole Chebyshev filters. The multiplexers are formed from a network of filters that stem from a common node. The measured bands include the combined effect of all of the optical elements between the FTS source and the antenna feed. The band edges, however, agree well with EM simulations of the microstrip multiplexers.
A diagram illustrating the operation of these multichroic pixels. A broadband sinuous antenna couples the radiation to a superconducting Niobium microstrip, which carries the radiation to a bank of band defining filters. The energy in each band is terminated onto a load resistor couple to a transition edge sensor on a thermally released bolometer island.
Centre de Congrès WTC, Grenoble, France
The frequency coverage of these pixels allows for simultaneous measurement of CMB and foreground polarization with the shared systematic uncertainties of a single experiment. Synchrotron radiation is strongest at lower frequencies while the thermal dust emission spectrum rises with frequency. A precision measurement of these foregrounds is essential to recovering the Bmode polarization signature from inflation.
The efficiency measured is consistent with the specifications of the wire grid polarizer used for the measurement.
Applications• POLARBEAR2/Simons Array
• Aritoki Suzuki's talk (Thursday Morning)• SPT3G
• Amy Bender's talk (Thursday Morning)• LiteBIRD
• Matsumura Tomotake's Talk (Thursday Morning)
• EBEX10K
A photograph of the test chip fabricated to test these new pixels. The antennas are tuned by by increasing or decreasing the the spacing between sinuous arms. The filters are tuned by modulating the geometry of the lumped filter element. All three sizes were fabricated simultaneously using standard optical lithography techniques.
High Frequency (HF) Triplexer
Mid Frequency (MF) Tetraplexer
Low Frequency (LF) Triplexer
The efficiency measured is consistent with the specifications of the wire grid polarizer used for the measurement.