  New mid-infrared HgCdTe (MCT) detector arrays developed in collaboration with
Teledyne Imaging Sensors (TIS) have paved the way for improved 10-$\mu$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-$\mu$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-$\mu$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
$\lambda/D$, providing improved contrast-limited performance compared to JWST
MIRI while operating at comparable wavelengths. We describe the performance
characteristics of the 13-$\mu$m GeoSnap array operating between 38 and 45K,
including quantum efficiency, well depth, linearity, gain, dark current, and
frequency-dependent (1/f) noise profile.
