New mid-infrared HgCdTe (MCT) detector arrays developed in collaboration with Teledyne Imaging Sensors (TIS) have paved the way for improved 10-$μ$m sensors for space- and ground-based observatories. Building on the successful development of longwave HAWAII-2RGs for space missions such as NEO Surveyor, we characterize the first 13-$μ$m GeoSnap detector manufactured to overcome the challenges of high background rates inherent in ground-based mid-IR astronomy. This test device merges the longwave HgCdTe photosensitive material with Teledyne's 2048x2048 GeoSnap-18 (18-$μ$m pixel) focal plane module, which is equipped with a capacitive transimpedance amplifier (CTIA) readout circuit paired with an onboard 14-bit analog-to-digital converter (ADC). The final assembly yields a mid-IR detector with high QE, fast readout (>85 Hz), large well depth (>1.2 million electrons), and linear readout. Longwave GeoSnap arrays would ideally be deployed on existing ground-based telescopes as well as the next generation of extremely large telescopes. While employing advanced adaptive optics (AO) along with state-of-the-art diffraction suppression techniques, instruments utilizing these detectors could attain background- and diffraction-limited imaging at inner working angles <10 $λ/D$, providing improved contrast-limited performance compared to JWST MIRI while operating at comparable wavelengths. We describe the performance characteristics of the 13-$μ$m GeoSnap array operating between 38 and 45K, including quantum efficiency, well depth, linearity, gain, dark current, and frequency-dependent (1/f) noise profile.

The modulation transfer function (MTF) is a useful measure in image quality analysis and performance budget determination. Sensitive long wavelength infrared (LWIR) detectors for astronomical space telescopes require slight modifications to the existing MTF measurement methods due to the increased prevalence of high dark current pixels. Presented here are the specifics of a modified slanted edge method to determine the MTF in lambda(c) > 10 mu m HgCdTe detectors to be used with the planned Near-Earth Object Surveyor Mission. The measured MTF at Nyquist using 6 mu m light is 0.22 +/- 0.02 and is 0.25 +/- 0.02 using 10 mu m light for both 250 and 350 mV of applied reverse bias. These measurements are from edge spread functions with median signal values around 50% of the well depth, as the MTF is expected to change with signal value due to two brighter-fatter type effects. The expected trends caused by the influences of these two effects and the expected trends with wavelength of absorbed photons are all observed. (C) 2022 Society of Photo-Optical Instrumentation Engineers (SPIE)

Near-Earth Object (NEO) Surveyor, a NASA planetary defense space mission, is currently in Phase B with a launch date in 2026. NEO Surveyor is an infrared telescope designed to detect and characterize Potentially Hazardous Asteroids (PHAs). The required sensors leverage the space flight heritage and further development over the last 15 years of HgCdTe arrays to detect infrared light spanning from 4 to 10 μm. NEO Surveyor will employ eight passively cooled HgCdTe Sensor Chip Assemblies (SCAs) across two bands, each band consisting of a 1x4 SCA mosaic to cover a wide field of view. Four of these SCAs have a >5.5 μm cutoff wavelength and cover the shorter 4-5.2 μm (NC1) band, while four SCAs will have a >10.5 μm cutoff wavelength and span the longer 6-10 μm (NC2) band. We present calibration and performance results from two recently produced pathfinder SCAs, one for each band, manufactured by Teledyne Imaging Sensors with development guidance from the University of Arizona, the University of Rochester, and JPL. Both devices demonstrate the requisite low dark current, high well depth, and high quantum efficiency, exceeding mission requirements.

NEO Surveyor is a NASA Planetary Defense Coordination Office mission designed to detect and track >2/3 of potentially hazardous asteroids >140 m in diameter during its 5-year prime mission. NEO Surveyor entered Phase B in June 2021 and is scheduled to launch in 2026 to survey the sky in two infrared bands. The infrared detectors are a key technology for the mission and have been the subject of focused development for more than a decade. In this paper, we report test results for recently produced detectors and describe design elements of the focal plane module relevant to operations for NEO Surveyor.

The status of various photovoltaic, photoconductive, BIB/IBC, superlattice, TES and KID technologies to produce arrays sensitive from 15 to [Formula: see text]m (Mid-infrared) will be reviewed to assess where reasonable investments should be made for SOFIA and other sub-orbital observatory instruments. These include HgCdTe, Si:As IBC, Si:Sb BIB, Ge:Ga, type 2 superlattice arrays of both III–V and II–VI materials and both TES and KID arrays. KID technologies for this wavelength region show promise, although to date there are no published experimental data on KID arrays for the mid-infrared.

One of the most important and well-established empirical results in astronomy is the Kennicutt–Schmidt relation between the density of interstellar gas and the rate at which that gas forms stars. A tight correlation between these quantities has long been measured at galactic scales. More recently, using surveys of YSOs, a KS relationship has been found within molecular clouds relating the surface density of star formation to the surface density of gas; however, the scaling of these laws varies significantly from cloud to cloud. In this Letter, we use a recently developed, high-accuracy catalog of young stellar objects from Spitzer combined with high-dynamic-range gas column density maps of 12 nearby (<1.5 kpc) molecular clouds from Herschel to re-examine the KS relation within individual molecular clouds. We find a tight, linear correlation between clouds’ star formation rate per unit area and their gas surface density normalized by the gas freefall time. The measured intracloud KS relation, which relates star formation rate to the volume density, extends over more than two orders of magnitude within each cloud and is nearly identical in each of the 12 clouds, implying a constant star formation efficiency per freefall time ϵ ff ≈ 0.026. The finding of a universal correlation within individual molecular clouds, including clouds that contain no massive stars or massive stellar feedback, favors models in which star formation is regulated by local processes such as turbulence or stellar feedback such as protostellar outflows, and disfavors models in which star formation is regulated only by galaxy properties or supernova feedback on galactic scales.

interstellar medium, and hydrodynamics on cosmic scales

He carried out fundamental, groundbreaking studies of the elemental abundances in stars during the 1950s and 1960s, when astronomers were just beginning to understand the role of stellar nucleosynthesis in determining the elemental abundances in the cosmos.His scientific interests were far broader than this, however, extending from highly theoretical work in fluid dynamics, plasma physics and general relativity, to observational investigations in radio, infrared, and optical astronomy, and his research subjects bridged broad scales, from planetary to cosmological.Larry was born on November 11, 1929, in the Bronx, New York.He developed his lifelong interest in astronomy as a young boy, and he met his future wife, Joanne Salomon, in the first grade.As a teenager he and his friends rode public transportation all over Manhattan to take advantage of the cultural and intellectual opportunitiessuch as the Hayden Planetarium-available within the metropolitan area, and he was

Improved measurement and calibration of detector behaviors will be crucial for future space missions, particularly those aiming to tackle outstanding questions in cosmology and exoplanet research. Similarly, many small detector effects, such as the nearest-neighbor interactions of the brighter-fatter effect and interpixel capacitance, will need to be considered to ensure measured signals are truly astronomical in origin. Laboratory measurements confirming the existence of an additional brighter-fatter type effect in HAWAII-1RG and HAWAII-2RG HgCdTe infrared arrays with cutoff wavelengths ranging from 5.7 to 16.7  μm are presented. This effect is similar in nature to the blooming observed in charge-coupled devices and is characterized by a pixel spontaneously sharing a current with its neighbors upon reaching saturation, serving to make the brightest sources appear fatter. In addition to exploring the cause and mechanism of current sharing for this effect, measurements for several arrays show the magnitude of the shared current is greater than 60% of the incoming photocurrent hitting the saturated pixel. A proof-of-concept correction method for this effect is also described along with the necessary next steps to improve this correction and investigate the amplitude of other nearest-neighbor interactions.

We explore the relation between the stellar mass surface density and the mass surface density of molecular hydrogen gas in 12 nearby molecular clouds that are located at <1.5 kpc distance. The sample clouds span an order-of-magnitude range in mass, size, and star formation rates. We use thermal dust emission from Herschel maps to probe the gas surface density and the young stellar objects from the most recent Spitzer Extended Solar Neighborhood Archive catalog to probe the stellar surface density. Using a star-sampled nearest neighbor technique to probe the star–gas surface density correlations at the scale of a few parsecs, we find that the stellar mass surface density varies as a power law of the gas mass surface density, with a power-law index of ∼2 in all the clouds. The consistent power-law index implies that star formation efficiency is directly correlated with gas column density, and no gas column density threshold for star formation is observed. We compare the observed correlations with the predictions from an analytical model of thermal fragmentation and with the synthetic observations of a recent hydrodynamic simulation of a turbulent star-forming molecular cloud. We find that the observed correlations are consistent for some clouds with the thermal fragmentation model and can be reproduced using the hydrodynamic simulations.

The depletion region around each p-n junction in HgCdTe HAWAII-2RG detector arrays decreases in volume as charge is collected, causing the pixel capacitance to change continuously throughout an integration period. This changing capacitance manifests as a steadily decreasing measured signal rate while observing a constant flux. Ignoring this nonlinear response to signal accumulation can lead to underestimating the number of detected photons by as much as 10%. Presented here are two methods, one simple and one complex, of measuring this signal nonlinearity and a theoretical framework behind a nonlinearity correction method. Additionally, experimental data are compared with simulations to explain methods to reduce noise in the nonlinearity measurement and identify deviations from the expected behavior that merit further study.

The University of Rochester infrared detector group is working together with Teledyne Imaging Sensors to develop mercury cadmium telluride (HgCdTe) 15 mu m cutoff wavelength detector arrays for future space missions. To reach the 15-mu m cutoff goal, we took an intermediate step by developing four similar to 13-mu m cutoff wavelength arrays to identify any unforeseen effects related to increasing the cutoff wavelength from the extensively characterized 10-mu m cutoff wavelength detector arrays developed for the NEOCam mission. The characterization of the similar to 13-mu m cutoff wavelength HgCdTe arrays at the University of Rochester allowed us to determine the key dark current mechanisms that limit the performance of these HgCdTe detector arrays at different temperatures and biases when the cutoff wavelength is increased. We present initial dark current and well depth measurements of a 15-mu m cutoff array that shows dark current values two orders of magnitude smaller at large reverse bias than would be expected from our previous best structures. (C) The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License.

Building on the successful development of the 10-mu m mercury cadmium telluride (HgCdTe) detector arrays for the proposed NEOCam mission, the University of Rochester Infrared Detector team and Teledyne Imaging Systems are working together to extend the cutoff wavelength of HgCdTe detector arrays initially to 13 mu m, with the ultimate goal of developing 15-mu m HgCdTe detector arrays for space and ground-based astronomy. The advantage of HgCdTe detector arrays is that they can operate at higher temperatures than the currently used arsenic doped silicon detector arrays at the longer wavelengths. Our infrared detector team at the University of Rochester has received and tested four 13-mu m detector arrays from Teledyne Imaging Systems with three different pixel designs, two of which are meant to reduce quantum tunneling dark current. The pixel design of one of these arrays has mitigated the effects of quantum tunneling dark currents for which we have been able to achieve, at a temperature of 28 K and applied bias of 350 mV, a well depth of at least 75ke(-) for 90% of the pixels with a median dark current of 1.8e(-)/s. These arrays have demonstrated encouraging results as we move forward to extending the cutoff wavelength to 15 mu m. (C) The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License.

The holy grail of ExoPlanet research is finding and characterizing terrestrial planets orbiting in the habitable zones of a neighboring stars. The first question to be answered is: does the planet have an atmosphere, and what is it’s composition. Theory and observation confirm that the one universal atmospheric component should be CO_2. Hence a successful mission must determine it’s presence. The most direct path to detection is through the enormously strong 15 micron vibration-rotation feature of CO_2, hence the technology we’re developing. Because of the CO_2 in the earth’s atmosphere, this requires a space observatory, such as the JWST. Our technology can also be used to detect water vapor and ozone in exoplanet atmospheres, the latter of which indicates abundant life, probably indicative of a ‘Cambrian Explosion’ event on the exoplanet.

A 2K x 2K 10 µm cutoff HgCdTe array for background-limited space astronomy has been developed by Teledyne Imaging Sensors to specifications set by JPL, and demonstrated by University of Rochester at a focal plane temperature of 40K for the proposed JPL Near-Earth Object Camera (NEOCam) survey mission under the NASA Planetary Defense Coordination Office. We describe the detector performance for the first large format monolithic HgCdTe detector array tested, including the dark current, well depth, dark current vs. temperature, quantum efficiency, latent image performance, and read noise.

Rochester Institute of Technology (RIT) and its collaborators at the University of Rochester and Harris Corporation are developing a room-temperature imaging Terahertz (THz) frequency detector using Si-MOSFET (Silicon Metal Oxide Semiconductor Field Effect Transistor) CMOS devices. They are implemented into a focal plane imaging array for use in many applications, such as transmission or penetration imaging and spectroscopy. Technology for THz detection is often extremely costly, due to either expensive detector materials or cryogenic cooling systems. However, the devices tested here are low-cost due to the use of conventional room temperature silicon CMOS technology. The devices operate from 170 to 250 GHz with an additional detector design has been fabricated for 30 THz (10 microns wavelength). Results are presented for the initial testing of single test structure FETs. These devices were designed with several different antenna configurations and a range of MOSFET design variations for evaluation. The primary goal of the work presented here is to determine the optimized detector design for the subsequent focal plane array implementation based on the largest responsivities and lowest noise-equivalent power (NEP). Transmission testing of the devices yields responsivities of about 100 to 1000 V/W and a NEP of about 0.5 to 10 nW·Hz-1/2. Through this evaluation and by utilizing signal amplification on the chip, signal modulation at higher frequencies, and smaller process sizes the performance of these devices will continue to improve in future designs.

With the recent success of our development of 10 micron HgCdTe infrared (IR) detector arrays,1,2 we have used what we learned and extended the cutoff wavelength to 13 microns. These 13 micron HgCdTe detector arrays can operate at higher temperatures than Si:As, e.g. in a properly designed spacecraft with passive cooling, the 13 micron IR array will work well at temperatures around 30K. We present the initial measurements of dark current, noise and quantum efficiency for the first deliveries of 13 micron HgCdTe detector arrays from Teledyne Imaging Sensors. We also discuss our plans to develop 15 micron cutoff HgCdTe detector arrays which would facilitate the detection of the broad CO2 absorption feature in the atmospheres of exoplanets, particularly those in the habitable zone of their host star.

The Near Earth Object Camera (NEOCam, Mainzer et al. 2015) is one of five NASA Discovery Class mission experiments selected for Phase A: down-select to one or two experiments will take place late in 2016. NEOCam will survey the sky in search of asteroids and comets, particularly those close to the Earth’s orbit. The NEOCam infrared telescope will have two infrared (IR) channels; one covering 4 to 5 microns, and one covering 6-10 microns. Both IR cameras will use multiple 2Kx2K pixel format HAWAII-2RG arrays with different cutoff wavelength HgCdTe detectors from Teledyne Imaging Sensors. Past development work by the University of Rochester with Teledyne Imaging Sensors and JPL (McMurtry et al. 2013, Dorn et al. 2016) focused upon bringing the 10 micron HgCdTe detector technology up to NASA TRL 6+. This work extends that development program to push the format from 1Kx1K to the larger 2Kx2K pixel array. We present results on the first 2Kx2K candidate 10 micron cutoff HgCdTe arrays, where we measured the dark current, read noise, and total noise.