We describe a novel cold neutron spectrometer under development at NIST optimized for wave vector resolved spectroscopy with incident energies between 2.1 meV and 20 meV and energy resolution from 0.05 meV (E i = 2.1 meV) to 3.0 meV (E i = 20 meV). By using a 1428 cm 2 double focusing PG (0 0 2) monochromator close to the National Institute of Standards and Technology (NIST) cold neutron source the instrument provides up to 5 × 10 8 neutrons cm −2 s −1 on a 8 cm 2 sample area. The measured performance is consistent with Monte Carlo simulations. The monochromating system, which includes radial collimators, three filters and a variable beam aperture, offers considerable flexibility in optimizing Q-resolution, energy resolution and intensity. The detector system will consist of an array of 20 channels which combined will subtend a solid angle of 0.2 sr. This is approximately a factor of 40 more than a conventional triple axis spectrometer. Each detector channel contains a vertically focusing double crystal analyzer system (DXAL) actuated by a single stepping motor. We find identical integrated reflectivity at approximately 10% coarser energy resolution for the 130 mosaic double bounce analyzer as compared to a conventional 25 analyzer at the same energy. The vertical focusing of the DXAL allows for smaller detectors for enhanced signal to noise with 8 • vertical acceptance. Options for post sample collimators and filters provide flexibility in the choice of scattered beam energy and wavevector resolution.
ABSTRACT. The FourStar Infrared Camera is a 4 K × 4 K near-infrared (1.0-2.4 μm) imager built for the Magellan 6.5 m Baade Telescope at Las Campanas Observatory, Chile. FourStar has an all-refractive optical system, four HAWAII-2RG detectors, and Teledyne electronics. The pixel scale of 0:159″ pixel À1 produces a 10:8 0 × 10:8 0 field of view. Ten filters are available across the Y , J, H, and K s bands. We present the optical, mechanical, thermal, electronic, and software design choices and their associated engineering implementations. The detector readout electronics, control system, and the automatic data acquisition hardware are also described. Laboratory and onsky performance data are presented. FourStar has excellent image quality, easily meeting the requirement of critically sampling the median seeing disk. The throughput is ≈0:5-0:6 across its wavelength coverage. Some early science results are presented.
PFS (Prime Focus Spectrograph), a next generation facility instrument on the 8.2-meter Subaru Telescope, is a very wide-field, massively multiplexed, optical and near-infrared spectrograph. Exploiting the Subaru prime focus, 2394 reconfigurable fibers will be distributed over the 1.3 deg field of view. The spectrograph has been designed with 3 arms of blue, red, and near-infrared cameras to simultaneously observe spectra from 380nm to 1260nm in one exposure at a resolution of ∼1.6−2.7Å. An international collaboration is developing this instrument under the initiative of Kavli IPMU. The project is now going into the construction phase aiming at undertaking system integration in 2017-2018 and subsequently carrying out engineering operations in 2018-2019. This article gives an overview of the instrument, current project status and future paths forward.
ABCC6 mediates release of ATP from hepatocytes into the blood. Extracellularly, ATP is converted into the mineralization inhibitor pyrophosphate. Consequently, inactivating mutations in ABCC6 give low plasma pyrophosphate and underlie the ectopic mineralization disorder pseudoxanthoma elasticum. How ABCC6 mediates cellular ATP release is still unknown. Fluorescent ABCC6 fusion proteins would allow mechanistic studies, but fluorophores attached to the ABCC6 Nor C-terminus result in intracellular retention and degradation. Here we describe that intramolecular introduction of fluorophores yields fully functional ABCC6 fusion proteins. A corresponding ABCC6 variant in which the catalytic glutamate of the second nucleotide binding domain was mutated, correctly routed to the plasma membrane but was inactive. Finally, N-terminal His 10 or FLAG tags did not affect activity of the fusion proteins, allowing their purification for biochemical characterization.
We present the design overview and on-telescope performance of the WIYN High Resolution Infrared Camera (WHIRC). As a dedicated near-infrared (0.8-2.5 μm) camera on the WIYN Tip-Tilt Module (WTTM) port, WHIRC can provide near-diffraction-limited imaging with an FWHM of ∼0:25 00 at K s with active WTTM correction and does deliver typical imaging with an FWHM of ∼0:6 00 without WTTM. WHIRC uses a 2048 × 2048 HgCdTe array from Raytheon's VIRGO line, which has been developed for the VISTA project. The WHIRC filter complement includes J, H, K s , and 10 narrowband filters. WHIRC's compact design makes it the smallest near-infrared camera with this capability. We determine a gain of 3:3 AE 0:2 e À ADU À1 via a photon transfer analysis and a readout noise of ∼19 e À . A measured dark current of 0:13 e À s À1 indicates that the cryostat is extremely light tight. A plate scale of 0:099 00 × 0:10 00 pixel À1 results in a field of view (FOV) of 3:3 0 × 3:4 0 , which is a compromise between the highest angular resolution achievable and the largest FOV correctable by WTTM. Measured throughput values (∼0:27 AE 0:02 in H band) are consistent with those predicted for WHIRC based on an analysis of individual optical elements and detector quantum efficiency (QE). WHIRC's photometric quality is better than ∼0:02 magnitudes in all bands. WHIRC is a general use instrument at the WIYN telescope enabling high-definition near-infrared imaging studies of a wide range of astronomical phenomena including star formation regions, stellar populations, and interstellar medium in nearby galaxies, high-z galaxies, and transient phenomena.
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