282 research outputs found
Development of an Array of Compound Refractive Lenses for Sub-Pixel Resolution, Large Field of View, and Time-Saving in Scanning Hard X-ray Microscopy
A two-dimensional array of compound refractive lenses (2D array of CRLs) designed for hard X-ray imaging with a 3.5 mm large field of view is presented. The array of CRLs consists of 2D polymer biconcave parabolic 34 × 34 multi-lenses fabricated via deep X-ray lithography. The developed refractive multi-lens array was applied for sub-pixel resolution scanning transmission X–ray microscopy; a raster scan with only 55 × 55 steps provides a 3.5 megapixel image. The optical element was experimentally characterized at the Diamond Light Source at 34 keV. An array of point foci with a 55 µm period and an average size of ca. 2.1 µm × 3.6 µm was achieved. In comparison with the conventional scanning transmission microscopy using one CRL, sub-pixel resolution scanning transmission hard X-ray microscopy enables a large field of view and short scanning time while keeping the high spatial resolution
Cosmic Origins Program Annual Technology Report
What is the Cosmic Origins (COR) Program? From ancient times, humans have looked up at the night sky and wondered: Are we alone? How did the universe come to be? How does the universe work? COR focuses on the second question. Scientists investigating this broad theme seek to understand the origin and evolution of the universe from the Big Bang to the present day, determining how the expanding universe grew into a grand cosmic web of dark matter enmeshed with galaxies and pristine gas, forming, merging, and evolving over time. COR also seeks to understand how stars and planets form from clouds in these galaxies to create the heavy elements that are essential to life starting with the first generation of stars to seed the universe, and continuing through the birth and eventual death of all subsequent generations of stars. The COR Programs purview includes the majority of the field known as astronomy, from antiquity to the present
Enabling Technologies for Next Generation Ultraviolet Astrophysics, Planetary, and Heliophysics Missions
Our study sought to create a new paradigm in UV instrument design, detector technology, and
optics that will form the technological foundation for a new generation of ultraviolet missions.
This study brought together scientists and technologists representing the broad community of
astrophysicists, planetary and heliophysics physicists, and technologists working in the UV.
Next generation UV missions require major advances in UV instrument design, optics and
detector technology. UV offers one of the few remaining areas of the electromagnetic spectrum
where this is possible, by combining improvements in detector quantum efficiency (5-10x),
optical coatings and higher-performance wide-field spectrometers (5-10x), and increasing
multiplex advantage (100-1000x).
At the same time, budgets for future missions are tightly constrained. Attention has begun to turn
to small and moderate class missions to provide new observational capabilities on timescales that
maintain scientific vitality. Developments in UV technology offer a comparatively unique
opportunity to conceive of small (Explorer) and moderate (Probe, Discovery, New Millennium)
class missions that offer breakthrough science.
Our study began with the science,
reviewing the breakthrough science
questions that compel the development of
new observational capabilities in the next
10-20 years. We invented a framework for
highlighting the objectives of UV
measurement capabilities: following the
history of baryons from the intergalactic
medium to stars and planets. In
astrophysics, next generation space UV missions will detect and map faint emission and
tomographically map absorption from intergalactic medium baryons that delineate the structure
of the Universe, map the circum-galactic medium that is the reservoir of galaxy-building gas,
map the warm-hot ISM of our Galaxy, explore star-formation within the Local group and beyond,
trace gas in proto-planetary disks and extended atmospheres of exoplanets, and record the
transient UV universe. Solar system planetary atmospheric physics and chemistry, aurorae,
surface composition and magnetospheric environments and interactions will be revealed using
UV spectroscopy. UV spectroscopy may even detect life on an exoplanet.
Our study concluded that with UV technology developments within reach over the next 5-
10 years, we can conceive moderate-class missions that will answer many of the compelling
science questions driving the field.
We reviewed the science measurement requirements for these pioneering new areas and
corresponding technology requirements. We reviewed and evaluated the emerging technologies,
and developed a figure of merit based on potential science impact, state of readiness, required
investment, and potential for highly leveraged progress in a 5-10 year horizon. From this we
were able to develop a strategy for technology development. Some of this technology
development will be subject to funding calls from federal agencies. A subset form a portfolio of
highly promising technologies that are ideal for funding from a KISS Development Program.
One of our study’s principal conclusions was that UV detector performance drives every aspect
of the scientific capability of future missions, and that two highly flexible detector technologies
were at the tipping point for major breakthroughs. These are Gen-2 borosilicate Atomic Layer
Deposition (ALD) coated microchannel plate detectors with GaN photocathodes, and ALDantireflection
(AR) coated, delta-doped photon-counting CCD detectors. Both offer the potential
for QE>50% combined with large formats and pixel counts, low background, and sky-limited
photon-counting performance over the 100-300 nm band. Ramped AR coatings for
spectroscopic detectors could achieve QE’s as high as 80%!
A second conclusion was that UV coatings are on the threshold of a major breakthrough. UV
coatings permeate every aspect of telescope and instrument design. Efficient, robust, ultra-thin
and highly uniform reflective coatings applied with Atomic Layer Deposition (ALD) offer the
possibility of high-performance, wide-field, highly-multiplexed UV spectrometers and a broadband
reach covering the scientifically critical 100-120 nm range (home of 50% of all atomic and
molecular resonance lines). Our study concluded that UV coating advances made possible by
ALD is the principle technology advance that will enable a joint UV-optical general
astrophysics and exoEarth imaging flagship mission.
A third conclusion was that the revolution in micro- and nano-fabrication technology offers a
cornucopia of new possibilities for revolutionary UV technology developments in the near future.
An immediate example is the application of new microlithography techniques to patterning UV
diffraction gratings that are highly efficient and designed to enable wide-field, high-resolution
spectroscopy. These techniques could support the development of new detectors that could
discriminate optical and UV photons and potentially energy-resolving detection.
Relatively modest investments in technology development over the next 5-10 years could
provide advances in detectors, coatings, diffractive elements, and filters that would result
in an effective increase in science capability of 100-1000!
The study brought together a diverse community, led to many new ideas and collaborations, and
brought cohesion and common purpose to UV practitioners. This will have a lasting and positive
impact on the future of our field
On evolution of CMOS image sensors
CMOS Image Sensors have become the principal technology in majority of digital cameras. They started replacing the film and Charge Coupled Devices in the last decade with the promise of lower cost, lower power requirement, higher integration and the potential of focal plane processing. However, the principal factor behind their success has been the ability to utilise the shrinkage in CMOS technology to make smaller pixels, and thereby have more resolution without increasing the cost. With the market of image sensors exploding courtesy their inte- gration with communication and computation devices, technology developers improved the CMOS processes to have better optical performance. Nevertheless, the promises of focal plane processing as well as on-chip integration have not been fulfilled. The market is still being pushed by the desire of having higher number of pixels and better image quality, however, differentiation is being difficult for any image sensor manufacturer. In the paper, we will explore potential disruptive growth directions for CMOS Image sensors and ways to achieve the same
Science Mission Directorate TechPort Records for 2019 STI-DAA Release
The role of the Science Mission Directorate (SMD) is to enable NASA to achieve its science goals in the context of the Nation's science agenda. SMD's strategic decisions regarding future missions and scientific pursuits are guided by Agency goals, input from the science community including the recommendations set forth in the National Research Council (NRC) decadal surveys and a commitment to preserve a balanced program across the major science disciplines. Toward this end, each of the four SMD science divisions -- Heliophysics, Earth Science, Planetary Science, and Astrophysics -- develops fundamental science questions upon which to base future research and mission programs
Diffractive X-ray Telescopes
Diffractive X-ray telescopes using zone plates, phase Fresnel lenses, or
related optical elements have the potential to provide astronomers with true
imaging capability with resolution several orders of magnitude better than
available in any other waveband. Lenses that would be relatively easy to
fabricate could have an angular resolution of the order of micro-arc-seconds or
even better, that would allow, for example, imaging of the distorted space-
time in the immediate vicinity of the super-massive black holes in the center
of active galaxies What then is precluding their immediate adoption? Extremely
long focal lengths, very limited bandwidth, and difficulty stabilizing the
image are the main problems. The history, and status of the development of such
lenses is reviewed here and the prospects for managing the challenges that they
present are discussed.Comment: 46 pages, 15 figures, invited review paper to be published in a
special issue on "X-Ray Focusing: Techniques and Applications" of the online
journal "X-Ray Optics & Instrumentation
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