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Jake A Connors

Publications and source records attributed to Jake A Connors.

4 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2024

Superfluid-Tight Cryogenic Receiver With Continuous Sub-Kelvin Cooling for EXCLAIM

The EXperiment for Cryogenic Large-Aperture Intensity Mapping (EXCLAIM) is a balloon-borne telescope designed to survey star formation over cosmological time scales using intensity mapping in the 420 – 540 GHz frequency range. EXCLAIM uses a fully cryogenic telescope coupled to six on-chip spectrometers featuring kinetic inductance detectors (KIDs) to achieve high sensitivity, allowing for fast integration in dark atmospheric windows. The telescope receiver is cooled to ≈ 1.7 K by immersion in a superfluid helium bath and enclosed in a superfluid-tight shell with a meta-material anti-reflection coated silicon window. In addition to the optics and the spectrometer package, the receiver contains the magnetic shielding, the cryogenic segment of the spectrometer readout, and the sub-Kelvin cooling system. A three-stage continuous adiabatic demagnetization refrigerator (CADR) keeps the detectors at 100 mK while a 4He sorption cooler provides a 900 mK thermal intercept for mechanical suspensions and coaxial cables. We present the design of the EXCLAIM receiver and report on the flight-like testing of major receiver components, including the superfluid-tight receiver window and the sub-Kelvin coolers.

continuous adiabatic demagnetization refrigerator↗
NASA NTRS2021

Experiment for Cryogenic Large-Aperture Intensity Mapping: Instrument Design

The EXperiment for Cryogenic Large-Aperture Intensity Mapping (EXCLAIM) is a balloon-borne tele-33scope designed to survey star formation in windows from the present to z=3.5. During this time, the rate of star34formation dropped dramatically, while dark matter continued to cluster. EXCLAIM maps the redshifted emission35of singly-ionized carbon lines and carbon monoxide using intensity mapping, which permits a blind and complete36survey of emitting gas through statistics of cumulative brightness fluctuations. EXCLAIM achieves high sensitivity37using a cryogenic telescope coupled to six integrated spectrometers employing kinetic inductance detectors covering38420540GHz with spectral resolving power R=512and angular resolution⇡40. The spectral resolving power and39cryogenic telescope allow the survey to access dark windows in the spectrum of emission from the upper atmosphere.40EXCLAIM will survey305 deg2in the Sloan Digital Sky Survey Stripe 82 field from a conventional balloon flight41in 2023. EXCLAIM will also map several galactic fields to study carbon monoxide and neutral carbon emission as42tracers of molecular gas. Here, we summarize the design phase of the mission.

Eric R Switzer↗
NASA NTRSDate not supplied

u-Spec Spectrometers for the EXCLAIM Instrument

The EXperiment for Cryogenic Large-aperture Intensity Mapping (EXCLAIM) is a cryogenic balloon-borne instrument that will map carbon monoxide and singly-ionized carbon emission lines across redshifts from 0to 3.5, using an intensity mapping approach. EXCLAIM will broaden our understanding of these elemental and molecular gases, and the role they play in star formation processes across cosmic time scales. The focal plane of EXCLAIM’s cryogenic telescope features sixμ-Spec spectrometers.μ-Spec is a compact, integrated grating-analog spectrometer, which uses meandered superconducting niobium microstrip transmission lines on a single-crystal silicon dielectric to synthesize the grating. It features superconducting aluminum microwave kinetic inductance detectors (MKIDs), also in a microstrip architecture. The spectrometers for EXCLAIM couple to the telescope optics via a hybrid planar antenna coupled to a silicon lenslet. The spectrometers operate from420−540 GHz with a resolving power R=λ/∆λ= 512, and employ an array of 355 MKIDs on each spectrometer. The spectrometer design targets a noise equivalent power (NEP) of 2×10−18W/√Hz (defined at the input to the main lobe of the spectrometer lenslet beam, within a 9◦half width), enabled by the cryogenic telescope environment, the sensitive MKID detectors, and the low dielectric loss of single-crystal silicon. We report on these spectrometers under development for EXCLAIM, providing an overview of the spectrometer and component designs, the spectrometer fabrication process, fabrication developments since previous prototype demonstrations, and the current status of their development for the EXCLAIM mission.

EXCLAIM Instrument↗