The status of MUSIC: the multiwavelength sub-millimeter inductance camera

Abstract

We present the status of MUSIC, the MUltiwavelength Sub/millimeter Inductance Camera, a new instrument for the Caltech Submillimeter Observatory. MUSIC is designed to have a 14', diffraction-limited field-of-view instrumented with 2304 detectors in 576 spatial pixels and four spectral bands at 0.87, 1.04, 1.33, and 1.98 mm. MUSIC will be used to study dusty star-forming galaxies, galaxy clusters via the Sunyaev-Zeldovich effect, and star formation in our own and nearby galaxies. MUSIC uses broadband superconducting phased-array slot-dipole antennas to form beams, lumpedelement on-chip bandpass filters to define spectral bands, and microwave kinetic inductance detectors to sense incoming light. The focal plane is fabricated in 8 tiles consisting of 72 spatial pixels each. It is coupled to the telescope via an ambient-temperature ellipsoidal mirror and a cold reimaging lens. A cold Lyot stop sits at the image of the primary mirror formed by the ellipsoidal mirror. Dielectric and metal-mesh filters are used to block thermal infrared and out-ofband radiation. The instrument uses a pulse tube cooler and 3 He/ 3 He/ 4He closed-cycle cooler to cool the focal plane to below 250 mK. A multilayer shield attenuates Earth's magnetic field. Each focal plane tile is read out by a single pair of coaxes and a HEMT amplifier. The readout system consists of 16 copies of custom-designed ADC/DAC and IF boards coupled to the CASPER ROACH platform. We focus on recent updates on the instrument design and results from the commissioning of the full camera in 2012.

HerMES: a search for high-redshift dusty galaxies in the HerMES Large Mode Survey – catalogue, number counts and early results

“…We observed four of our 500-micron-bright sources (HELMS RED 3, HELMS RED 4, HELMS RED 6 and HELMS RED 7) at the Caltech Submillimeter Observatory using the Multiwavelength Submillimeter Inductance Camera (MUSIC, Sayers et al 2014). MUSIC observes simultaneously in four bands centred on frequencies of 143, 213, 272, and 326 GHz (2.09, 1.4, 1.1 and 0.92 mm in wavelength), with PSFs that have FWHMs of 48 , 36 , 32 , and 29 , respectively.…”

Cryogenic LED pixel-to-frequency mapper for kinetic inductance detector arrays

“…MKIDs have received great attention in astronomy [6][7][8] and other sensitive detection fields [9,10] because they are simple to fabricate and easy to multiplex into large arrays. A MKID array with thousands of pixels can be fabricated with one or a few standard photo-lithography steps and read out with a pair of coaxial cables into the cryostat.…”

“…Although the resonators are designed to have evenly spaced frequencies by systematically varying the size of interdigitated capacitor (IDC), the measured resonance frequencies clearly deviate from such a regular pattern, making it impossible to unambiguously correspond a physical pixel to its actual frequency from the transmission data. A common approach to identification is cryogenic beam mapping, which typically requires a vacuum-sealed window, IR filters to control radiative load, and complicated coupling optics [6,7].…”

Applications for Microwave Kinetic Induction Detectors in Advanced Instrumentation

“…DemoCam was used for tests and to gather general know-how for MUSIC but was also used for first astronomical observations [25,26]. MUSIC [27][28][29][30][31] was intended to reach 576 individual pixels sensitive to 4 different colors at 150, 230, 290, and 350 GHz (2.0, 1.3, 1.0, and 0.86 mm). MUSIC used the same broadband, superconducting phased-array slot-dipole antennas coupled to Al/Nb MKIDs as DemoCam, just with more bandpass filters and 4 MKIDs per pixel for a total detector count of 2304.…”