The Multiwavelength Sub/millimeter Inductance Camera (MUSIC) is a four-band photometric imaging camera operating from the Caltech Submillimeter Observatory (CSO). MUSIC is designed to utilize 2304 microwave kinetic inductance detectors (MKIDs), with 576 MKIDs for each observing band centered on 150, 230, 290, and 350 GHz. MUSIC’s field of view (FOV) is 14′ square, and the point-spread functions (PSFs) in the four observing bands have 45′′, 31′′, 25′′, and 22′′ full-widths at half maximum (FWHM). The camera was installed in April 2012 with 25% of its nominal detector count in each band, and has subsequently completed three short sets of engineering observations and one longer duration set of early science observations. Recent results from on-sky characterization of the instrument during these observing runs are presented, including achieved map- based sensitivities from deep integrations, along with results from lab-based measurements made during the same period. In addition, recent upgrades to MUSIC, which are expected to significantly improve the sensitivity of the camera, are described.
The Tomographic Ionized carbon Mapping Experiment (TIME) is a multi-phased experiment that will topographically map [CII] emission from the Epoch of Reionization. We are developing lithographed spectrometers that couple to TES bolometers in anticipation of the second generation instrument. Our design intentionally mirrors many features of the parallel SuperSpec project, inductively coupling power from a trunk-line microstrip onto half-wave resonators. The resonators couple to a rat-race hybrids that feeds TES bolometers. Our 25 channel prototype shows spectrally positioned lines roughly matching design with a receiver optical efficiency of 15-20%, a level that is dominated by loss in components outside the spectrometer.
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 3He/ 3He/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.
We will present the design and implementation, along with calculations and some measurements of the performance,
of the room-temperature and cryogenic optics for MUSIC, a new (sub)millimeter camera we are
developing for the Caltech Submm Observatory (CSO). The design consists of two focusing elements in addition
to the CSO primary and secondary mirrors: a warm off-axis elliptical mirror and a cryogenic (4K) lens. These
optics will provide a 14 arcmin field of view that is diffraction limited in all four of the MUSIC observing bands
(2.00, 1.33, 1.02, and 0.86 mm). A cold (4K) Lyot stop will be used to define the primary mirror illumination,
which will be maximized while keeping spillover at the sub 1% level. The MUSIC focal plane will be populated
with broadband phased antenna arrays that efficiently couple to factor of (see manuscript) 3 in bandwidth,1, 2 and each pixel on
the focal plane will be read out via a set of four lumped element filters that define the MUSIC observing bands
(i.e., each pixel on the focal plane simultaneously observes in all four bands). Finally, a series of dielectric and
metal-mesh low pass filters have been implemented to reduce the optical power load on the MUSIC cryogenic
stages to a quasi-negligible level while maintaining good transmission in-band.
MUSIC (Multicolor Submillimeter kinetic Inductance Camera) is a new facility instrument for the Caltech Submillimeter
Observatory (Mauna Kea, Hawaii) developed as a collaborative effect of Caltech, JPL, the University
of Colorado at Boulder and UC Santa Barbara, and is due for initial commissioning in early 2011. MUSIC utilizes
a new class of superconducting photon detectors known as microwave kinetic inductance detectors (MKIDs), an
emergent technology that offers considerable advantages over current types of detectors for submillimeter and
millimeter direct detection. MUSIC will operate a focal plane of 576 spatial pixels, where each pixel is a slot line
antenna coupled to multiple detectors through on-chip, lumped-element filters, allowing simultaneously imaging
in four bands at 0.86, 1.02, 1.33 and 2.00 mm.
The MUSIC instrument is designed for closed-cycle operation, combining a pulse tube cooler with a two-stage
Helium-3 adsorption refrigerator, providing a focal plane temperature of 0.25 K with intermediate temperature
stages at approximately 50, 4 and 0.4 K for buffering heat loads and heat sinking of optical filters. Detector
readout is achieved using semi-rigid coaxial cables from room temperature to the focal plane, with cryogenic
HEMT amplifiers operating at 4 K. Several hundred detectors may be multiplexed in frequency space through
one signal line and amplifier.
This paper discusses the design of the instrument cryogenic hardware, including a number of features unique to
the implementation of superconducting detectors. Predicted performance data for the instrument system will
also be presented and discussed.
Detectors employing superconducting microwave kinetic inductance detectors (MKIDs) can be read out by
measuring changes in either the resonator frequency or dissipation. We will discuss the pros and cons of both
methods, in particular, the readout method strategies being explored for the Multiwavelength Sub/millimeter
Inductance Camera (MUSIC) to be commissioned at the CSO in 2010. As predicted theoretically and observed
experimentally, the frequency responsivity is larger than the dissipation responsivity, by a factor of 2-4 under
typical conditions. In the absence of any other noise contributions, it should be easier to overcome amplifier
noise by simply using frequency readout. The resonators, however, exhibit excess frequency noise which has been
ascribed to a surface distribution of two-level fluctuators sensitive to specific device geometries and fabrication
techniques. Impressive dark noise performance has been achieved using modified resonator geometries employing
interdigitated capacitors (IDCs). To date, our noise measurement and modeling efforts have assumed an onresonance
readout, with the carrier power set well below the nonlinear regime. Several experimental indicators
suggested to us that the optimal readout technique may in fact require a higher readout power, with the carrier
tuned somewhat off resonance, and that a careful systematic study of the optimal readout conditions was needed.
We will present the results of such a study, and discuss the optimum readout conditions as well as the performance
that can be achieved relative to BLIP.
MUSIC (the Multiwavelength Submillimeter kinetic Inductance Camera) is an instrument being developed for
the Caltech Submillimeter Observatory by Caltech, JPL, the University of Colorado, and UCSB. MUSIC uses
microwave kinetic inductance detectors (MKIDs) - superconducting micro-resonators - as photon detectors. The
readout is almost entirely at room temperature and is highly multiplexed. MUSIC will have 576 spatial pixels
in four bands at 850, 1100, 1300 and 2000 microns. MUSIC is scheduled for deployment at the CSO in the
winter of 2010/2011. We present an overview of the camera design and readout and describe the current status
of the instrument and some results from the highly successful May/June 2010 observing run at the CSO with the
prototype camera, which verified the performance of the complete system (optics, antennas/filters, resonators,
and readout) and produced the first simultaneous 3-color observations with any MKID camera.
Proc. SPIE. 7741, Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy V
KEYWORDS: Signal to noise ratio, Electronics, Clocks, Resonators, Interference (communication), Amplifiers, Field programmable gate arrays, Signal processing, Field effect transistors, Microwave radiation
This paper will present the design, implementation, performance analysis of an open source readout system
for arrays of microwave kinetic inductance detectors (MKID) for mm/submm astronomy. The readout system
will perform frequency domain multiplexed real-time complex microwave transmission measurements in order
to monitor the instantaneous resonance frequency and dissipation of superconducting microresonators. Each
readout unit will be able to cover up to 550 MHz bandwidth and readout 256 complex frequency channels
simultaneously. The digital electronics include the customized DAC, ADC, IF system and the FPGA based
signal processing hardware developed by CASPER group.1-7 The entire system is open sourced, and can be
customized to meet challenging requirement in many applications: e.g. MKID, MSQUID etc.
We present the results of the latest multicolor Microwave Kinetic Inductance Detector (MKID) focal plane arrays
in the submillimeter. The new detectors on the arrays are superconducting resonators which combine a coplanar
waveguide section with an interdigitated capacitor, or IDC. To avoid out-of-band pickup by the capacitor, a
stepped-impedance filter is used to prevent radiation from reaching the absorptive aluminum section of the
resonator. These arrays are tested in the preliminary demonstration instrument, DemoCam, a precursor to the
Multicolor Submillimeter Inductance Camera, MUSIC. We present laboratory results of the responsivity to light
both in the laboratory and at the Caltech Submillimeter Observatory. We assess the performance of the detectors
in filtering out-of-band radiation, and find the level of excess load and its effect on detector performance. We
also look at the array design characteristics, and the implications for the optimization of sensitivities expected