NuSTAR hard x-ray optics design and performance

Koglin, Jason E.; An, Hongjun; Blaedel, Kenneth L.; Brejnholt, Nicolai; Christensen, Finn Erland; Craig, William W.; Decker, Todd A.; Hailey, Charles J.; Hale, Layton C.; Harrison, Fiona A.; Jensen, Christian Damsgaard; Madsen, Kristin K.; Mori, Kaya; Pivovaroff, M. J.; Tajiri, Gordon; Zhang, William W.

doi:10.1117/12.826724

Cited by 35 publications

(26 citation statements)

References 7 publications

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“…The X-ray optics and detector benches are separated by a stiff mast that includes a mechanism with the capability of making small adjustments to optimize the location of the optical axis on the focal plane detectors (see Fig.1). The X-ray optics bench consists of two Wolter-I conical approximation 3 mirror modules, each with 133 shells coated with multiple layers of W/Si and Pt/C, limiting the highest efficient reflectivity to the Pt 78.4 keV K-edge 4,5,6 . The focal plane bench is mounted on the spacecraft bus and consists of two independent solid state photon counting detector modules (FPMA & B), each with a 2x2 array of CdZnTe (CZT) crystal detectors, surrounded by CsI anti-coincidence shielding.…”

Section: The Nustar Observatorymentioning

confidence: 99%

NuSTAR observatory science operations: on-orbit acclimation

et al. 2014

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The Nuclear Spectroscopic Telescope Array (NuSTAR) is the first focusing high energy (3-79 keV) X-ray observatory. The NuSTAR project is led by Caltech, which hosts the Science Operations Center (SOC), with mission operations managed by UCB Space Sciences Laboratory. We present an overview of NuSTAR science operations and describe the on-orbit performance of the observatory. The SOC is enhancing science operations to serve the community with a guest observing program beginning in 2015. We present some of the challenges and approaches taken by the SOC to operating a full service space observatory that maximizes the scientific return from the mission.

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Section: The Nustar Observatorymentioning

confidence: 99%

NuSTAR observatory science operations: on-orbit acclimation

et al. 2014

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“…It is comprised of thermally formed glass substrates deposited with Pt/C multilayers to enhance X-ray reflectivity in the 0.5-10 keV band. The techniques and infrastructure used in fabricating the CAST XRT were originally developed 35 to make the two hard X-ray telescopes that are flying on NASA's NuSTAR satellite 36 . The optical prescription and multilayer coatings were optimized when considering factors including: the physical constraints of the CAST experiment; the predicted axion spectrum; and the quantum efficiency of the Micromegas detector 37 .…”

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confidence: 99%

New CAST limit on the axion–photon interaction

2017

Nature Phys

879

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Hypothetical low-mass particles, such as axions, provide a compelling explanation for the dark matter in the universe. Such particles are expected to emerge abundantly from the hot interior of stars. To test this prediction, the CERN Axion Solar Telescope (CAST) uses a 9 T refurbished Large Hadron Collider test magnet directed towards the Sun. In the strong magnetic field, solar axions can be converted to X-ray photons which can be recorded by X-ray detectors. In the 2013-2015 run, thanks to low-background detectors and a new X-ray telescope, the signal-to-noise ratio was increased by about a factor of three. Here, we report the best limit on the axion-photon coupling strength (0.66 × 10 −10 GeV −1 at 95% confidence level) set by CAST, which now reaches similar levels to the most restrictive astrophysical bounds.A dvancing the low-energy frontier is a key endeavour in the worldwide quest for particle physics beyond the standard model and in the effort to identify dark matter 1,2 . Nearly massless pseudoscalar bosons, often generically called axions, are particularly promising because they appear in many extensions of the standard model. They can be dark matter in the form of classical field oscillations that were excited in the early universe, notably by the re-alignment mechanism 3 . One particularly well motivated case is the quantum chromodynamics (QCD) axion, the eponym for all such particles. The existence of this new lowmass boson follows from the Peccei-Quinn mechanism as an explanation why QCD is perfectly time-reversal invariant within current experimental precision 3 .Axions were often termed 'invisible' because of their extremely feeble interactions, yet they are the target of a fast-growing international landscape of experiments. Numerous existing and foreseen projects assume that axions are the galactic dark matter and use a variety of techniques that are sensitive to different interaction channels and optimal in different mass ranges 4 . Independently of the dark-matter assumption, one can search for new forces mediated by these low-mass bosons 5 or the back-reaction on spinning black holes (superradiance) 6 . Stellar energy-loss arguments provide restrictive limits that can guide experimental efforts, and in some cases may even suggest new loss channels 3,7,8 .The least model-dependent search strategies use the production and detection of axions and similar particles by their generic twophoton coupling. It is given by the vertex L aγ = −(1/4) g aγ F µν F µν a = g aγ E · B a, where a is the axion field, F the electromagnetic field-strength tensor, and g aγ a coupling constant of dimension (energy) −1 . Notice that we use natural units with = c = k B = 1. This vertex enables the decay a → γ γ , the Primakoff production in stars-that is, the γ → a scattering in the Coulomb fields of charged particles in the stellar plasma-and the coherent conversion a ↔ γ in laboratory or astrophysical B-fields 9,10 .The helioscope concept, in particular, uses a dipole magnet directed at the Sun to convert axions to...

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“…The NuSTAR optics design has been described elsewhere, 4,5 and the fabrication of the NuSTAR flight optics is described in detail in these proceedings (Craig et al, "Fabrication of the NuSTAR Flight Optics", SPIE 8147-15, 2011). 6 Here we briefly summarize the aspects of the optics design and fabrication that are of particular importance to calibration of the effective area and point spread response function (PSF).…”

Section: Optics Design and Fabricationmentioning

confidence: 99%

First results from the ground calibration of the NuSTAR flight optics

Koglin

Barrière

et al. 2011

SPIE Proceedings

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NuSTAR is a hard X-ray satellite experiment to be launched in 2012. Two optics with 10.15 m focal length focus Xrays with energies between 5 and 80 keV onto CdZnTe detectors located at the end of a deployable mast. The FM1 and FM2 flight optics were built at the same time based on the same design and with very similar components, and thus the performance of both is expected to be very similar. We provide an overview of calibration data that is being used to build an optics response model for each optic and describe initial results for energies above 10 keV from the ground calibration of the flight optics. From a preliminary analysis of the data, our current best determination of the overall HPD of both the FM1 and FM2 flight optics is 52", and nearly independent of energy. The statistical error is negligible, and a preliminary estimate of the systematic error is of order 4". The as-measured effective area and HPD meet the toplevel NuSTAR mission sensitivity requirements.

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NuSTAR hard x-ray optics design and performance

Cited by 35 publications

References 7 publications

NuSTAR observatory science operations: on-orbit acclimation

NuSTAR observatory science operations: on-orbit acclimation

New CAST limit on the axion–photon interaction

First results from the ground calibration of the NuSTAR flight optics

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