Sridhar Manthripragada
A5016338201- Advanced Semiconductor Detectors and Materials
- Astronomy and Astrophysical Research
- Pulsars and Gravitational Waves Research
- Adaptive optics and wavefront sensing
- Gamma-ray bursts and supernovae
- Geophysics and Gravity Measurements
- Stellar, planetary, and galactic studies
- CCD and CMOS Imaging Sensors
- Spectroscopy and Laser Applications
- Astro and Planetary Science
- Advanced MEMS and NEMS Technologies
- Spacecraft and Cryogenic Technologies
- Astrophysical Phenomena and Observations
- Astronomical Observations and Instrumentation
- Superconducting Materials and Applications
- Planetary Science and Exploration
- Laser Material Processing Techniques
- Integrated Circuits and Semiconductor Failure Analysis
- Infrared Target Detection Methodologies
- Particle Accelerators and Free-Electron Lasers
- Spacecraft Design and Technology
- Geophysics and Sensor Technology
- Isotope Analysis in Ecology
- Biomedical Text Mining and Ontologies
- Inertial Sensor and Navigation
PES University
2023
Goddard Space Flight Center
1998-2021
PSR J0740$+$6620 has a gravitational mass of $2.08\pm 0.07~M_\odot$, which is the highest reliably determined any neutron star. As result, measurement its radius will provide unique insight into properties star core matter at high densities. Here we report based on fits rotating hot spot patterns to Neutron Star Interior Composition Explorer (NICER) and X-ray Multi-Mirror (XMM-Newton) observations. We find that equatorial circumferential $13.7^{+2.6}_{-1.5}$ km (68%). apply our measurement,...
During 2014 and 2015, NASA's Neutron star Interior Composition Explorer (NICER) mission proceeded success- fully through Phase C, Design Development. An X-ray (0.2-12 keV) astrophysics payload destined for the International Space Station, NICER is manifested launch in early 2017 on Commercial Resupply Services SpaceX-11 flight. Its scientific objectives are to investigate internal structure, dynamics, energetics of neutron stars, densest objects universe. flight components including optics,...
Over a 10-month period during 2013 and early 2014, development of the Neutron star Interior Composition Explorer (NICER) mission [1] proceeded through Phase B, Mission Definition. An external attached payload on International Space Station (ISS), NICER is scheduled to launch in 2016 for an 18-month baseline mission. Its prime scientific focus in-depth investigation neutron stars—objects that compress up two Solar masses into volume size city—accomplished observations 0.2–12 keV X-rays,...
The first terrestrial gravitational wave interferometers have dramatically underscored the scientific value of observing Universe through an entirely different window, and folding this new channel information with traditional astronomical data for a multimessenger view. Laser Interferometer Space Antenna (LISA) will broaden reach astronomy by conducting survey millihertz sky, detecting tens thousands individual astrophysical sources ranging from white-dwarf binaries in our own galaxy to...
The OSIRIS-REx Visible and Infrared Spectrometer (OVIRS) is a point spectrometer covering the spectral range of 0.4 to 4.3 microns (25,000–2300 cm−1). Its primary purpose map surface composition asteroid Bennu, target sample return mission. information it returns will help guide selection site. It also provide global context for high spatial resolution spectra that can be related spatially unresolved terrestrial observations asteroids. compact, low-mass (17.8 kg), power efficient (8.8 W...
We describe how the James Webb Space Telescope (JWST) Near‐Infrared Spectrograph's (NIRSpec) detectors will be read out, and present a model of noise scales with number multiple nondestructive reads sampling up ramp. believe that this model, which is validated using real simulated test data, applicable to most astronomical near‐infrared instruments. some nonideal behaviors have been observed in engineering‐grade NIRSpec detectors, demonstrate they are unlikely affect sensitivity, operations,...
The main objective is to look into Text Summarization techniques and their application within the medical domain. challenge catalogue, standardize biomedical literature its enormous size which currently constitutes more than 30 Mn citations abstracts are part of PubMed database. need for research on text summarization twofold. With increasing in 3V's (velocity, variety volume) data (Medical usually accompanied by images), along with growing regulation, it becomes important interpret...
The James Webb Space Telescope's (JWST) Near Infrared Spectrograph (NIRSpec) incorporates two 5 μm cutoff (λ<sub>co</sub> =5 μm) 2048×2048 pixel Teledyne HgCdTe HAWAII-2RG sensor chip assemblies. These detector arrays, and the SIDECAR application specific integrated circuits that control them, are operated in space at T ~ 37 K. In this article, we provide a brief introduction to NIRSpec, its subsystem (DS), readout radiation environment, present snapshot of developmental status...
This whitepaper summarizes the status of ESA-led Laser Interferometer Space Antenna (LISA) mission and advocates for an increased US role within ‘medium’ category. The LISA science case, concept, technical readiness, organizational partnerships are summarized broad scenarios participation described.
The James Webb Space Telescope, an infrared-optimized space telescope being developed by NASA for launch in 2014, will utilize cutting-edge detector technology its investigation of fundamental questions astrophysics. JWST's near infrared spectrograph, NIRSpec utilizes two 2048 × HdCdTe arrays with Sidecar ASIC readout electronics Teledyne to provide spectral coverage from 0.6 microns 5 microns. We present recent test and calibration results the "pathfinder subsystem" as well data processing...
The Near-Infrared Spectrograph (NIRSpec) is the James Webb Space Telescope's primary near-infrared spectrograph. NASA providing NIRSpec detector subsystem, which consists of focal plane array, electronics, cable harnesses, and software. array comprises two closely-butted λ<sub>co</sub> ~ 5 μm Rockwell HAWAII-2RG sensor chip assemblies. After briefly describing instrument, we summarize some driving requirements for discuss baseline architecture (and alternatives), presents recent test...
We present early results from the performance test development for Detector Subsystem of Near-Infrared Spectrograph (NIRSpec). NIRSpec will be primary near-infrared spectrograph on James Webb Space Telescope (JWST). The consists a Focal Plane Assembly containing two Teledyne HAWAII-2RG arrays, SIDECAR cryogenic application specific integrated circuits, and warm Electronics box. Characterization Laboratory at NASA's Goddard Flight Center perform characterization tests. In this paper, we...
We present new timing and spectral analyses of PSR J1412+7922 (Calvera) J1849-0001, which are only seen as pulsars in X-rays, based on observations conducted with the Neutron Star Interior Composition Explorer (NICER). obtain updated substantially improved pulse ephemerides compared to previous X-ray studies, well spectra that can be well-fit by simple blackbodies and/or a power law. Our refined measurements enable deeper searches for pulsations at other wavelengths sensitive targeted...
We present interim results from the characterization test development for Detector Subsystem of Near-Infrared Spectrograph (NIRSpec). NIRSpec will be primary near-infrared spectrograph on James Webb Space Telescope (JWST). The consists a Focal Plane Assembly containing two Teledyne HAWAII-2RG arrays, SIDECAR cryogenic application specific integrated circuits, and warm Electronics box. Characterization Laboratory at NASA's Goddard Flight Center perform tests. In this paper, we update initial...
The James Webb Space Telescope (JWST) Near Infrared Spectrograph (NIRSpec) incorporates two 5 μm cutoff (λ<sub>co</sub> =5 μm) 2048×2048 pixel Teledyne HgCdTe HAWAII-2RG sensor chip assemblies. These detector arrays, and the SIDECAR application specific integrated circuits that control them, are operated in space at Τ ~ 37 K. This article focuses on measured performance of first flight-candidate, near-flight candidate, arrays. flight-packaged arrays meet NIRSpec's...
The Near Infrared Spectrograph (NIRSpec) will be the James Webb Space Telescope's (JWST's) primary near-infrared spectrograph. NIRSpec is a multi-object spectrograph with fixed-slit and integral field modes. EADS/Astrium building for European Agency (ESA), NASA providing detector subsystem programmable multi-aperture mask. In this paper, we summarize recent progress on including tests demonstrating that JWST's Rockwell HAWAII-2RG sensor chip assemblies have achieved Technology Readiness...
The near infrared spectrograph (NIRSpec) will be the James Webb Space Telescope's (JWSTs) primary near-infrared spectrograph. NIRSpec is a multi-object with fixed-slit and integral field modes. EADS/Astrium building for European Agency (ESA), NASA providing detector subsystem programmable multi-aperture mask. In this presentation we present an overview of (DS)
The composite infrared spctrometer (CIRS) is an important instrument for the upcoming Cassini mission sensing (IR) radiation from Saturanian planetary system. We have delivered a linear, ten element, mercury cadmium telluride (HgCdTe) photoconductive detector array use on focal plane 3 (FP3), which responsible detecting 9.1 micrometer to 16.6 wavelength range. Reliable HgCdTe detectors require robust passivation, low-stress zinc sulfide (ZnS) anti-reflection (AR) coating with good adhesion,...
GOES long wave sounder (LWS) detector requirements have always pushed the state-of-the-art for longwave detectors operating in vicinity of 102 K. Performance and yield acceptable been problems continue to be important issues affecting performance instruments both present future design. GSFC has examining new device operational concepts aimed at producing significant improvements yield. Our approach directed towards mitigating deleterious effects small geometry HgCdTe PC devices under heavy...
The composite infrared spectrometer (CIRS) instrument, an important component of the Cassini mission, consists 3 focal plane arrays for sensing IR radiation Saturnian planetary system. Goddard Space Flight Center has fabricated, tested, and delivered high performance, 10- element HgCdTe photoconductive (PC) use on CIRS FP3, responsible detection in 9.1 to 16.7 micrometers spectral band. flight array peak responsivity 100 percent above specification, detectivity 30 or more a cutoff wavelength...
Probably the most important factor in producing HgCdTe detectors of high performance is surface passivation. A good passivant for PC accumulates thereby reflecting minority carriers from imperfections and increasing carrier lifetime. variety passivants are known used to various degrees, including sulfides, fluorides, oxides, others. One problems with that they tend accumulate too strongly, thus non-optimal results. We have developed a new passivation process which passivates without strong...