Investigating reciprocity failure in 1.7-micron cut-off HgCdTe detectors

Flux dependent non-linearity (reciprocity failure) in HgCdTe NIR detectors with 1.7 micron cut-off was investigated. A dedicated test station was designed and built to measure reciprocity failure over the full dynamic range of near infrared detectors. For flux levels between 1 and 100,000 photons/sec a limiting sensitivity to reciprocity failure of 0.3%/decade was achieved. First measurements on several engineering grade 1.7 micron cut-off HgCdTe detectors show a wide range of reciprocity failure, from less than 0.5%/decade to about 10%/decade. For at least two of the tested detectors, significant spatial variation in the effect was observed. No indication for wavelength dependency was found. The origin of reciprocity failure is currently not well understood. In this paper we present details of our experimental set-up and show the results of measurements for several detectors.Comment: 11 pages, 10 figures, to appear in " Astronomical Telescopes and Instrumentation: High Energy, Optical, and Infrared Detectors for Astronomy IV", Proceedings of SPIE Vol. 774

Near-Infrared Instrumentation and Millimeter-Wave Simulations For Cosmological Surveys.

The evolution of the Universe is well characterized by the concordance lCDM cosmological model where structure formation is seeded by cold dark matter and accelerated expansion is driven by the cosmological constant. Understanding the history and fate of the Universe requires precise measurements of cosmological parameters. Finding them inconsistent may lead to a more fundamental physical theory. I explore observable probes of cosmological parameters as well as instrumental effects that may obfuscate them. I develop a framework for simulating millimeter-wave skies including galaxy clusters' Sunyaev-Zel'dovich (SZ) signature. This framework includes astrophysical and instrumental effects. Its primary use is in testing systematic effects resulting from joining intrinsic profile variations and mass dependencies with observational uncertainties and signal extraction techniques as well as multi-wavelength studies. I demonstrate that the signal recovered using Matched Filter is very sensitive to (SZ) profile shapes and potentially leads to biases. I then consider the impact of galaxy cluster selection and characterization in the maxBCG cluster catalog on recovering a stacked SZ signal in light of recently measured biases. I find that accounting for the mass calibration uncertainty and mis-centering of galaxy clusters may explain the majority of the observed discrepancy. In addition, contrary to others' findings, I conclude that the X-ray sub-sample of maxBCG clusters is similarly affected. My findings suggest that the SZ signal can indeed serve as an alternate mass calibration technique. I finally focus on instrumental effects in near-infrared (NIR) detectors designed for large surveys of the cosmos. I first characterize the flux dependent non-linearity known as reciprocity failure and find that it can be as large as 10% per decade in flux change but is suppressed by cooling the detectors. I then thoroughly study the quantum efficiency (QE) of a single NIR device under different environmental and illumination conditions and conclude that it can vary significantly. Careful accounting of various sources of uncertainty suggests that some observers may be too confident in the quality of their QE measurements.PhDPhysicsUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/102326/1/tomaszbi_1.pd