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Author

Jeff Apple

Bio: Jeff Apple is an academic researcher from Marshall Space Flight Center. The author has contributed to research in topics: Telescope & Payload. The author has an hindex of 7, co-authored 14 publications receiving 212 citations.

Papers
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Journal ArticleDOI
TL;DR: HERO as mentioned in this paper is a balloon-borne hard-x-ray telescope that utilizes grazing incidence optics, which can provide unprecented sensitivity in the hard x-ray region and will achieve milliCrab-level sensitivity in a typical 3-hour balloon-flight observation and 50 microCrab sensitivity on ultra-long-duration flights.
Abstract: We are developing a balloon-borne hard-x-ray telescope that utilizes grazing incidence optics. Termed HERO, for High-Energy Replicated Optics, the instrument will provide unprecented sensitivity in the hard-x-ray region and will achieve milliCrab-level sensitivity in a typical 3-hour balloon-flight observation and 50 microCrab sensitivity on ultra-long-duration flights. A recent proof-of-concept flight, featuring a small number of mirror shells captured the first focused hard-x-ray images of galactic x-ray sources. Full details of the payload, its expected future performance and its recent measurements are provided.

80 citations

Journal ArticleDOI
TL;DR: In this paper, a star camera was designed, built, and flight-tested for pointing a pointed balloon-borne experiment at altitude around 40 km. The camera and lens are commercially available, off-the-shelf components, but require a custom-built baffle to reduce stray light, especially near the sunlit limb of the balloon.
Abstract: We have designed, built, and flight-tested a new star camera for daytime guiding of pointed balloon-borne experiments at altitudes around 40 km. The camera and lens are commercially available, off-the-shelf components, but require a custom-built baffle to reduce stray light, especially near the sunlit limb of the balloon. This new camera, which operates in the 600- to 1000-nm region of the spectrum, successfully provides daytime aspect information of approx. 10 arcsec resolution for two distinct star fields near the galactic plane. The detected scattered-light backgrounds show good agreement with the Air Force MODTRAN models used to design the camera, but the daytime stellar magnitude limit was lower than expected due to longitudinal chromatic aberration in the lens. Replacing the commercial lens with a custom-built lens should allow the system to track stars in any arbitrary area of the sky during the daytime.

38 citations

Proceedings ArticleDOI
28 Nov 2000
TL;DR: In this article, the authors developed high-energy grazing-incidence replicated optics for a balloon-borne hard-x-ray telescope, which will have 170 cm2 of effective collecting area at 40 keV and 130 square cm at 60 keV with <= 30 arc seconds half power diameter.
Abstract: We are developing high-energy grazing-incidence replicated optics for a balloon-borne hard-x-ray telescope. When completed, the instrument will have 170 cm2 of effective collecting area at 40 keV and 130 square cm at 60 keV with <= 30 arc seconds half power diameter. This payload will offer unprecedented sensitivity in the hard-x-ray region, with around 250 microCrab sensitivity on long-duration flights and 50-100 microCrab on ultra- long-duration balloon missions The payload consists of 16 mirror modules, each with 14 nested mirrors made from a high-strength nickel alloy, and a corresponding array of 16 focal plane detectors. An engineering demonstration flight is scheduled for the Spring of 2000, using just two mirror modules each with 3 shells, above a pair of gas-scintillation-proportional counters. This flight is intended to test a newly designed gondola pointing and aspect system and the stability of the optical bench design. The first scientific flight of the full payload is scheduled for the Fall of 2002. Full details of the payload and its capabilities will be presented together with data from various mirror-module tests. If available data from the first flight will also be presented.

24 citations

Journal ArticleDOI
TL;DR: The first high-altitude balloon flight of a wide-field hard X-ray coded-aperture telescope ProtoEXIST1, which was launched from the Columbia Scientific Balloon Facility at Ft. Sumner, New Mexico on October 9, 2009, was reported in this paper.
Abstract: We successfully carried out the first high-altitude balloon flight of a wide-field hard X-ray coded-aperture telescope ProtoEXIST1 , which was launched from the Columbia Scientific Balloon Facility at Ft. Sumner, New Mexico on October 9, 2009. ProtoEXIST1 is the first implementation of an advanced CdZnTe (CZT) imaging detector in our ongoing program to establish the technology required for next generation wide-field hard X-ray telescopes such as the High Energy Telescope (HET) in the Energetic X-ray Imaging Survey Telescope ( EXIST ). The CZT detector plane in ProtoEXIST1 consists of an 8×8 array of closely tiled 2 cm×2 cm×0.5 cm thick pixellated CZT crystals, each with 8×8 pixels, mounted on a set of readout electronics boards and covering a 256 cm 2 active area with 2.5 mm pixels. A tungsten mask, mounted at 90 cm above the detector provides shadowgrams of X-ray sources in the 30–600 keV band for imaging, allowing a fully coded field of view of 9°×9° (and 19°×19° for 50% coding fraction) with an angular resolution of 20 ′ . In order to reduce the background radiation, the detector is surrounded by semi-graded (Pb/Sn/Cu) passive shields on the four sides all the way to the mask. On the back side, a 26 cm×26 cm×2 cm CsI(Na) active shield provides signals to tag charged particle induced events as well as ≳ 100 keV background photons from below. The flight duration was only about 7.5 h due to strong winds (60 knots) at float altitude (38–39 km). Throughout the flight, the CZT detector performed excellently. The telescope observed Cyg X-1, a bright black hole binary system, for ∼ 1 h at the end of the flight. Despite a few problems with the pointing and aspect systems that caused the telescope to track about 6.4° off the target, the analysis of the Cyg X-1 data revealed an X-ray source at 7.2 σ in the 30–100 keV energy band at the expected location from the optical images taken by the onboard daytime star camera. The success of this first flight is very encouraging for the future development of the advanced CZT imaging detectors ( ProtoEXIST2 , with 0.6 mm pixels), which will take advantage of the modularization architecture employed in ProtoEXIST1 .

16 citations

Journal ArticleDOI
01 Oct 2012
TL;DR: The ProtoEXIST2 CZT detector plane consists of 64 of 5 mm thick 2 cm × 2 cm CZTs with a minimal gap as discussed by the authors, which is a prototype for a next generation hard X-ray imager MlRAX-HXI on board Lattes, a spacecraft from the Agencia Espacial Brasilieira.
Abstract: We have assembled a tiled array (220 cm2) of fine pixel (0.6 mm) imaging CZT detectors for a balloon borne widefield hard X-ray telescope, ProtoEXIST2. ProtoEXIST2 is a prototype experiment for a next generation hard X-ray imager MlRAX-HXI on board Lattes, a spacecraft from the Agencia Espacial Brasilieira. MlRAX will survey the 5 to 200 keV sky of Galactic bulge, adjoining southern Galactic plane and the extragalactic sky with 6' angular resolution. This survey will open a vast discovery space in timing studies of accretion neutron stars and black holes. The ProtoEXIST2 CZT detector plane consists of 64 of 5 mm thick 2 cm × 2 cm CZT crystals tiled with a minimal gap. MIRAX will consist of 4 such detector planes, each of which will be imaged with its own coded-aperture mask. We present the packaging architecture and assembly procedure of the ProtoEXIST2 detector. On 2012, Oct 10, we conducted a successful high altitude balloon experiment of the ProtoEXISTl and 2 telescopes, which demonstrates their technology readiness for space application. Both telescopes performed flawlessly during the flight as well as on the ground. We report the results of pre-flight ground calibration and the preliminary results for the detector performance in the balloon flight.

16 citations


Cited by
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Journal ArticleDOI
Fiona A. Harrison1, William W. Craig2, William W. Craig3, Finn Erland Christensen4, Charles J. Hailey5, William W. Zhang6, Steven E. Boggs3, Daniel Stern1, W. Rick Cook1, Karl Forster1, Paolo Giommi, Brian W. Grefenstette1, Yunjin Kim1, Takao Kitaguchi7, Jason E. Koglin5, Kristin K. Madsen1, Peter H. Mao1, Hiromasa Miyasaka1, Kaya Mori5, M. Perri8, Michael J. Pivovaroff2, Simonetta Puccetti8, Vikram Rana1, Niels Jørgen Stenfeldt Westergaard4, J. L. Willis1, Andreas Zoglauer3, Hongjun An9, Matteo Bachetti10, Matteo Bachetti11, Nicolas M. Barrière3, Eric C. Bellm1, Varun Bhalerao12, Varun Bhalerao1, Nicolai Brejnholt4, Felix Fuerst1, Carl Christian Liebe1, Craig B. Markwardt6, Melania Nynka5, Julia Vogel2, Dominic J. Walton1, Daniel R. Wik6, David M. Alexander13, L. R. Cominsky14, Ann Hornschemeier6, Allan Hornstrup4, Victoria M. Kaspi9, Greg Madejski, Giorgio Matt15, S. Molendi7, David M. Smith16, John A. Tomsick3, Marco Ajello3, David R. Ballantyne17, Mislav Baloković1, Didier Barret11, Didier Barret10, Franz E. Bauer18, Roger Blandford8, W. Niel Brandt19, Laura Brenneman20, James Chiang8, Deepto Chakrabarty21, Jérôme Chenevez4, Andrea Comastri7, Francois Dufour9, Martin Elvis20, Andrew C. Fabian22, Duncan Farrah23, Chris L. Fryer24, Eric V. Gotthelf5, Jonathan E. Grindlay20, D. J. Helfand25, Roman Krivonos3, David L. Meier1, Jon M. Miller26, Lorenzo Natalucci7, Patrick Ogle1, Eran O. Ofek27, Andrew Ptak6, Stephen P. Reynolds28, Jane R. Rigby6, Gianpiero Tagliaferri7, Stephen E. Thorsett29, Ezequiel Treister30, C. Megan Urry31 
TL;DR: The Nuclear Spectroscopic Telescope Array (NuSTAR) as discussed by the authors is the first focusing high-energy X-ray telescope in orbit, which operates in the band from 3 to 79 keV.
Abstract: The Nuclear Spectroscopic Telescope Array (NuSTAR) mission, launched on 2012 June 13, is the first focusing high-energy X-ray telescope in orbit. NuSTAR operates in the band from 3 to 79 keV, extending the sensitivity of focusing far beyond the ~10 keV high-energy cutoff achieved by all previous X-ray satellites. The inherently low background associated with concentrating the X-ray light enables NuSTAR to probe the hard X-ray sky with a more than 100-fold improvement in sensitivity over the collimated or coded mask instruments that have operated in this bandpass. Using its unprecedented combination of sensitivity and spatial and spectral resolution, NuSTAR will pursue five primary scientific objectives: (1) probe obscured active galactic nucleus (AGN) activity out to the peak epoch of galaxy assembly in the universe (at z ≾ 2) by surveying selected regions of the sky; (2) study the population of hard X-ray-emitting compact objects in the Galaxy by mapping the central regions of the Milky Way; (3) study the non-thermal radiation in young supernova remnants, both the hard X-ray continuum and the emission from the radioactive element ^(44)Ti; (4) observe blazars contemporaneously with ground-based radio, optical, and TeV telescopes, as well as with Fermi and Swift, to constrain the structure of AGN jets; and (5) observe line and continuum emission from core-collapse supernovae in the Local Group, and from nearby Type Ia events, to constrain explosion models. During its baseline two-year mission, NuSTAR will also undertake a broad program of targeted observations. The observatory consists of two co-aligned grazing-incidence X-ray telescopes pointed at celestial targets by a three-axis stabilized spacecraft. Deployed into a 600 km, near-circular, 6° inclination orbit, the observatory has now completed commissioning, and is performing consistent with pre-launch expectations. NuSTAR is now executing its primary science mission, and with an expected orbit lifetime of 10 yr, we anticipate proposing a guest investigator program, to begin in late 2014.

1,966 citations

Journal ArticleDOI
TL;DR: The International Axion Observatory (IAXO) as mentioned in this paper is the most powerful axion helioscope, reaching sensitivity to axion-photon couplings down to a few × 10−12 GeV−1 and thus probing a large fraction of the currently unexplored axion and ALP parameter space.
Abstract: The International Axion Observatory (IAXO) will be a forth generation axion helioscope. As its primary physics goal, IAXO will look for axions or axion-like particles (ALPs) originating in the Sun via the Primakoff conversion of the solar plasma photons. In terms of signal-to-noise ratio, IAXO will be about 4–5 orders of magnitude more sensitive than CAST, currently the most powerful axion helioscope, reaching sensitivity to axion-photon couplings down to a few × 10−12 GeV−1 and thus probing a large fraction of the currently unexplored axion and ALP parameter space. IAXO will also be sensitive to solar axions produced by mechanisms mediated by the axion-electron coupling gae with sensitivity — for the first time — to values of gae not previously excluded by astrophysics. With several other possible physics cases, IAXO has the potential to serve as a multi-purpose facility for generic axion and ALP research in the next decade. In this paper we present the conceptual design of IAXO, which follows the layout of an enhanced axion helioscope, based on a purpose-built 20 m-long 8-coils toroidal superconducting magnet. All the eight 60cm-diameter magnet bores are equipped with focusing x-ray optics, able to focus the signal photons into ~ 0.2 cm2 spots that are imaged by ultra-low-background Micromegas x-ray detectors. The magnet is built into a structure with elevation and azimuth drives that will allow for solar tracking for ~ 12 h each day.

318 citations

Proceedings ArticleDOI
TL;DR: The Nuclear Spectroscopic Telescope Array (NuSTAR) is a NASA Small Explorer mission that will carry the first focusing hard X-ray (5 - 80 keV) telescope to orbit as discussed by the authors.
Abstract: The Nuclear Spectroscopic Telescope Array (NuSTAR) is a NASA Small Explorer mission that will carry the first focusing hard X-ray (5 - 80 keV) telescope to orbit. NuSTAR will offer a factor 50 - 100 sensitivity improvement compared to previous collimated or coded mask imagers that have operated in this energy band. In addition, NuSTAR provides sub-arcminute imaging with good spectral resolution over a 12-arcminute field of view. After launch, NuSTAR will carry out a two-year primary science mission that focuses on four key programs: studying the evolution of massive black holes through surveys carried out in fields with excellent multiwavelength coverage, understanding the population of compact objects and the nature of the massive black hole in the center of the Milky Way, constraining explosion dynamics and nucleosynthesis in supernovae, and probing the nature of particle acceleration in relativistic jets in active galactic nuclei. A number of additional observations will be included in the primary mission, and a. guest observer program will be proposed for an extended mission to expand the range of scientific targets. The payload consists of two co-aligned depth-graded multilayer coated grazing incidence optics focused onto solid state CdZnTe pixel detectors. To be launched in early 2012 on a Pegasus rocket into a low-inclination Earth orbit. NuSTAR largely avoids SAA passages, and will therefore have low and stable detector backgrounds. The telescope achieves a 10.15-meter focal length through on-orbit deployment of all mast. An aspect and alignment metrology system enable reconstruction of the absolute aspect and variations in the telescope alignment resulting from mast flexure during ground data processing. Data will be publicly available at GSFC's High Energy Astrophysics Science Archive Research Center (HEASARC) following validation at the science operations center located at Caltech.

140 citations

01 Jul 2003
TL;DR: INTEGRAL, (INTErnational Gamma-Ray Astrophysics Laboratory) is an astronomical satellite for observing the gamma-ray sky which was launched in October, 2002 as mentioned in this paper, and is planned for 2 years with a possible extension for up to 5 years.
Abstract: INTEGRAL, (INTErnational Gamma-Ray Astrophysics Laboratory) is an astronomical satellite for observing the gamma-ray sky. It was launched in October, 2002. The use of INTEGRAL is planned for 2 years with a possible extension for up to 5 years. The INTEGRAL spacecraft features 4 instruments: a gamma ray spectrometer, a gamma ray imager, two X-ray monitors and an optical monitoring camera.

112 citations

Journal ArticleDOI
TL;DR: A pixellated high energy X-ray detector instrument to be used in a variety of imaging applications and the novel interconnect technology is described and how the system is performing in several target applications is described.
Abstract: We have developed a pixellated high energy X-ray detector instrument to be used in a variety of imaging applications. The instrument consists of either a Cadmium Zinc Telluride or Cadmium Telluride (Cd(Zn)Te) detector bump-bonded to a large area ASIC and packaged with a high performance data acquisition system. The 80 by 80 pixels each of 250 μm by 250 μm give better than 1 keV FWHM energy resolution at 59.5 keV and 1.5 keV FWHM at 141 keV, at the same time providing a high speed imaging performance. This system uses a relatively simple wire-bonded interconnection scheme but this is being upgraded to allow multiple modules to be used with very small dead space. The readout system and the novel interconnect technology is described and how the system is performing in several target applications.

110 citations