Cleanliness specifications for infrared detector arrays are usually so stringent that effects are neglibile. However, the specifications determine only the level of particulates and areal density of molecular layer on the surface, but the chemical composition of these contaminants are not specified. Here, we use a model to assess the impact on system quantum efficiency from possible contaminants that could accidentally transfer or cryopump to the detector during instrument or spacecraft testing and on orbit operation. Contaminant layers thin enough to meet typical specifications, < 0.5μgram/cm2, have a negligible effect on the net quantum efficiency of the detector, provided that the contaminant does not react with the detector surface, Performance impacts from these contaminant plating onto the surface become important for thicknesses 5 - 50μgram/cm2. Importantly, detectable change in the ”ripple” of the anti reflection coating occurs at these coverages and can enhance the system quantum efficiency. This is a factor 10 less coverage for which loss from molecular absorption lines is important. Thus, should contamination be suspected during instrument test or flight, detailed modelling of the layer on the detector and response to very well known calibrations sources would be useful to determine the impact on detector performance.
In support of the European space agency (ESA) Euclid mission, NASA is responsible for the evaluation of the H2RG mercury cadmium telluride (MCT) detectors and electronics assemblies fabricated by Teledyne imaging systems. The detector evaluation is performed in the detector characterization laboratory (DCL) at the NASA Goddard space flight center (GSFC) in close collaboration with engineers and scientists from the jet propulsion laboratory (JPL) and the Euclid project. The Euclid near infrared spectrometer and imaging photometer (NISP) will perform large area optical and spectroscopic sky surveys in the 0.9-2.02 μm infrared (IR) region. The NISP instrument will contain sixteen detector arrays each coupled to a Teledyne SIDECAR application specific integrated circuit (ASIC). The focal plane will operate at 100K and the SIDECAR ASIC will be in close proximity operating at a slightly higher temperature of 137K. This paper will describe the test configuration, performance tests and results of the latest engineering run, also known as pilot run 3 (PR3), consisting of four H2RG detectors operating simultaneously. Performance data will be presented on; noise, spectral quantum efficiency, dark current, persistence, pixel yield, pixel to pixel uniformity, linearity, inter pixel crosstalk, full well and dynamic range, power dissipation, thermal response and unit cell input sensitivity.
We present the Wide Field Infra-Red Survey Telescope (WFIRST) wide field instrument concept based on the reuse of a
2.4m telescope recently made available to NASA. Two instrument channels are described, a wide field channel
(~0.8x0.4degrees, 300Mpix, imaging and spectroscopy over 0.76-2.0um), and an integral field unit (3x3 arcsec, 1Mpix,
R{2pixel} ~100 over 0.6-2.0um). For this mission concept, the telescope, instruments, and spacecraft are in a
geosynchronous orbit and are designed for serviceability. This instrument can accomplish not only the baseline exoplanet
microlensing, dark energy, and infrared surveys for WFIRST, but can perform at higher angular resolution and with
deeper observations. This enables significant opportunities for more capable general observer programs. The emphasis
on achieving very good imaging stability is maintained from the previous work.
Establishing improved spectrophotometric standards is important for a broad range of missions and is relevant
to many astrophysical problems. ACCESS, “Absolute Color Calibration Experiment for Standard Stars”, is a
series of rocket-borne sub-orbital missions and ground-based experiments designed to enable improvements in
the precision of the astrophysical flux scale through the transfer of absolute laboratory detector standards from
the National Institute of Standards and Technology (NIST) to a network of stellar standards with a calibration
accuracy of 1% and a spectral resolving power of 500 across the 0.35-1.7µm bandpass.
The focal plane assembly for the Thermal Infrared Sensor (TIRS) instrument on NASA's Landsat Data Continuity
Mission (LDCM) consists of three 512 x 640 GaAs Quantum Well Infrared Photodetector (QWIP) arrays. The three
arrays are precisely mounted and aligned on a silicon carrier substrate to provide a continuous viewing swath of 1850
pixels in two spectral bands defined by filters placed in close proximity to the detector surfaces. The QWIP arrays are
hybridized to Indigo ISC9803 readout integrated circuits (ROICs). QWIP arrays were evaluated from four laboratories;
QmagiQ, (Nashua, NH), Army Research Laboratory, (Adelphi, MD), NASA/ Goddard Space Flight Center, (Greenbelt,
MD) and Thales, (Palaiseau, France). All were found to be suitable. The final discriminating parameter was the spectral
uniformity of individual pixels relative to each other. The performance of the QWIP arrays and the fully assembled,
NASA flight-qualified, focal plane assembly will be reviewed. An overview of the focal plane assembly including the
construction and test requirements of the focal plane will also be described.
ACCESS, Absolute Color Calibration Experiment for Standard Stars, is a series of rocket-borne sub-orbital
missions and ground-based experiments designed to enable improvements in the precision of the astrophysical
flux scale through the transfer of absolute laboratory detector standards from the National Institute of Standards
and Technology (NIST) to a network of stellar standards with a calibration accuracy of 1% and a spectral resolving
power of 500 across the 0.35.1.7μm bandpass.
Establishing improved spectrophotometric standards is important for a broad range of missions and is relevant
to many astrophysical problems. Systematic errors associated with problems such as dark energy now compete
with the statistical errors and thus limit our ability to answer fundamental questions in astrophysics.
The ACCESS design, calibration strategy, and an updated preliminary performance estimate are discussed.
We are implementing nano- and micro-technologies to develop a miniaturized electron impact ionization mass
spectrometer for planetary science. Microfabrication technology is used to fabricate the ion and electron optics, and a
carbon nanotube (CNT) cathode is used to generate the ionizing electron beam. Future NASA planetary science
missions demand miniaturized, low power mass spectrometers that exhibit high resolution and sensitivity to search for
evidence of past and present habitability on the surface and in the atmosphere of priority targets such as Mars, Titan,
Enceladus, Venus, Europa, and short-period comets. Toward this objective, we are developing a miniature, high
resolution reflectron time-of-flight mass spectrometer (Mini TOF-MS) that features a low-power CNT field emission
electron impact ionization source and microfabricated ion optics and reflectron mass analyzer in a parallel-plate
geometry that is scalable. Charged particle electrodynamic modeling (SIMION 8.0.4) is employed to guide the iterative
design of electron and ion optic components and to characterize the overall performance of the Mini TOF-MS device via
simulation. Miniature (< 1000 cm3) TOF-MS designs (ion source, mass analyzer, detector only) demonstrate simulated
mass resolutions > 600 at sensitivity levels on the order of 10-3 cps/molecule N2/cc while consuming 1.3 W of power and
are comparable to current spaceflight mass spectrometers. Higher performance designs have also been simulated and
indicate mass resolutions ~1000, though at the expense of sensitivity and instrument volume.
Solar system exploration and the anticipated discovery of biomarker molecules is driving the development of a new
miniature time-of-flight (TOF) mass spectrometer (MS). Space flight science investigations become more feasible
through instrument miniaturization, which reduces size, mass, and power consumption. However, miniaturization of
space flight mass spectrometers is increasingly difficult using current component technology. Micro electro mechanical
systems (MEMS) and nano electro mechanical systems (NEMS) technologies offer the potential of reducing size by
orders of magnitude, providing significant system requirement benefits as well. Historically, TOF mass spectrometry
has been limited to large separation distances as ion mass analysis depends upon the ion flight path. Increased TOF MS
system miniaturization may be realized employing newly available high speed computing electronics, coupled with
MEMS and NEMS components. Recent efforts at NASA Goddard Space Flight Center in the development of a
miniaturized TOF mass spectrometer with integral MEMS and NEMS components are presented. A systems overview,
design and prototype, MEMS silicon ion lenses, a carbon nanotube electron gun, ionization methods, as well as
performance data and relevant applications are discussed.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.