The EXperiment for Cryogenic Large-Aperture Intensity Mapping (EXCLAIM) will constrain star formation over cosmic time by carrying out a blind and complete census of redshifted carbon monoxide (CO) and ionized carbon ([CII]) emission in cross-correlation with galaxy survey data in redshift windows from the present to z=3.5 with a fully cryogenic, balloon-borne telescope. EXCLAIM will carry out extragalactic and Galactic surveys in a conventional balloon flight planned for 2023. EXCLAIM will be the first instrument to deploy µ-Spec silicon integrated spectrometers with a spectral resolving power R=512 covering 420-540 GHz. We summarize the design, science goals, and status of EXCLAIM.
KEYWORDS: Sensors, Resonators, Digital signal processing, Inductance, Data conversion, Multiplexing, Signal to noise ratio, Frequency combs, Signal attenuation
The Prime-Cam instrument on the Fred Young Submillimeter Telescope (FYST) is expected to be the largest deployment of millimeter and submillimeter sensitive kinetic inductance detectors to date. To read out these arrays efficiently, a microwave frequency multiplexed readout has been designed to run on the Xilinx Radio Frequency System on a Chip (RFSoC). The RFSoC has dramatically improved every category of size, weight, power, cost, and bandwidth over the previous generation readout systems. We describe a baseline firmware design which can read out four independent RF networks each with 500 MHz of bandwidth and 1000 detectors for ∼30 W. The overall readout architecture is a combination of hardware, gateware/firmware, software, and network design. The requirements of the readout are driven by the 850 GHz instrument module of the seven-module Prime-Cam instrument. These requirements along with other constraints which have led to critical design choices are highlighted. Preliminary measurements of the system phase noise and dynamic range are presented.
The experiment for cryogenic large-aperture intensity mapping (EXCLAIM) is a balloon-borne telescope designed to survey star formation in windows from the present to z = 3.5. During this time, the rate of star formation dropped dramatically, while dark matter continued to cluster. EXCLAIM maps the redshifted emission of singly ionized carbon lines and carbon monoxide using intensity mapping, which permits a blind and complete survey of emitting gas through statistics of cumulative brightness fluctuations. EXCLAIM achieves high sensitivity using a cryogenic telescope coupled to six integrated spectrometers employing kinetic inductance detectors covering 420 to 540 GHz with spectral resolving power R = 512 and angular resolution ≈4 arc min. The spectral resolving power and cryogenic telescope allow the survey to access dark windows in the spectrum of emission from the upper atmosphere. EXCLAIM will survey 305 deg2 in the Sloan Digital Sky Survey Stripe 82 field from a conventional balloon flight in 2023. EXCLAIM will also map several galactic fields to study carbon monoxide and neutral carbon emission as tracers of molecular gas. We summarize the design phase of the mission.
Publisher’s Note: This paper, originally published on 22 December 2020, was replaced with a corrected/revised version on 12 March 2021. If you downloaded the original PDF but are unable to access the revision, please contact SPIE Digital Library Customer Service for assistance.
AliCPT-1 is the first CMB degree scale polarimeter to be deployed to the Tibetan plateau at 5,250m asl. AliCPT-1 is a 95/150GHz 72cm aperture, two lens refracting telescope cooled down to 4K. Alumina lenses image the CMB on a 636mm wide focal plane. The modularized focal plane consists of dichroic polarization-sensitive Transition-Edge Sensors (TESes). Each module includes 1,704 optically active TESes fabricated on a 6in Silicon wafer. Each TES array is read out with a microwave multiplexing with a multiplexing factor up to 2,000. Such large factor has allowed to consider 10's of thousands of detectors in a practical way, enabling to design a receiver that can operate up to 19 TES arrays for a total of 32,300 TESes. AliCPT-1 leverages the technological advancements of AdvACT and BICEP-3. The cryostat receiver is currently under integration and testing. Here we present the AliCPT-1 receiver, underlying how the optimized design meets the experimental requirements.
The EXperiment for Cryogenic Large-Aperture Intensity Mapping (EXCLAIM) is a balloon-borne far-infrared telescope that will survey galactic formation history over cosmological time scales with redshifts between 0 and 3.5. EXCLAIM will measure the statistics of brightness fluctuations of redshifted cumulative carbon monoxide and singly ionized carbon line emissions, following an intensity mapping approach. EXCLAIM will couple all-cryogenic optical elements to six μ-Spec spectrometer modules, operating at 420-540 GHz with a spectral resolution of 512 and featuring microwave kinetic inductance detectors. Here, we present an overview of the mission and its development status.
KEYWORDS: Superconductors, Multiplexing, Sensors, Data communications, Telecommunications, Microwave radiation, Astronomy, System on a chip, Algorithm development, Telescopes
We describe the development of a reconfigurable frequency multiplexed readout system for superconducting arrays. This system is an upgrade to the ROACH2 based readout system we have developed for a number of balloon-borne and ground-based instruments including BLAST-TNG, OLIMPO, MUSCAT, Superspec and TolTEC. Specifically our development has targeted the RFSoC ZCU111 evaluation board of which the size, weight, power, and instantaneous bandwidth have made it an attractive candidate for future balloon-borne or space-based astronomical instruments. Applications for the new readout system focus primarily on: frequency multiplexed superconducting nanowires single-photon detectors, Kinetic inductance detectors, Transition Edge Sensors, and Quantum Capacitance detectors. We will discuss the overlapping readout requirements that drive the general firmware architecture. Preliminary measurements with the new readout system using different detector technologies will also be presented.
Microwave kinetic inductance detectors (MKIDs) operate through means of a superconducting resonator that changes resonant frequency and quality factor when incident photons are absorbed in the superconducting material. Incident power on MKIDs is determined by reading out the phase and amplitude of a tone injected into each detector. However, if the incident power on an MKID changes too drastically and the resonant frequency moves too far from the probe tone, amplitude information becomes useless and the detector is effectively out of commission until a VNA sweep is used to relocate resonances. Here we present the designs and preliminary results of a tone-tracking firmware that uses phase information to maintain an on-resonance probe tone at all times, removing the need for time-intensive VNA sweeps during observations and effectively maximizing the dynamic range of MKIDs. We will conclude with a discussion on future NASA missions that hope implement this tone-tracking design.
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