Showing papers by "Charles J. Hailey published in 2011"

Fabrication of the NuSTAR flight optics

Abstract: We describe the fabrication of the two NuSTAR flight optics modules. The NuSTAR optics modules are glass-graphiteepoxy composite structures to be employed for the first time in space-based X-ray optics by NuSTAR, a NASA Small Explorer schedule for launch in February 2012. We discuss the optics manufacturing process, the qualification and environmental testing performed, and briefly discuss the results of X-ray performance testing of the two modules. The integration and alignment of the completed flight optics modules into the NuSTAR instrument is described as are the optics module thermal shields.

First results from the ground calibration of the NuSTAR flight optics

Abstract: 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.

NuSTAR ground calibration: The Rainwater Memorial Calibration Facility (RaMCaF)

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. The ground calibration of the three flight optics was carried out at the Rainwater Memorial Calibration Facility (RaMCaF) built for this purpose. In this article we present the facility and its use for the ground calibration of the three optics.

The Rainwater Memorial Calibration Facility for X-Ray Optics

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. The ground calibration of the optics posed a challenge as the need to suppress finite source distance effects over the full optic and the energy range of interest were unique requirements not met by any existing facility. In this paper we present the requirements for the NuSTAR optics ground calibration, and how the Rainwater Memorial Calibration Facility, RaMCaF, is designed to meet the calibration requirements. The nearly 175 m long beamline sports a 48 cm diameter 5–100 keV X-ray beam and is capable of carrying out detailed studies of large diameter optic elements, such as the NuSTAR optics, as well as flat multilayer-coated Silicon wafers.

The General Antiparticle Spectrometer (GAPS) - Hunt for dark matter using low energy antideuterons

Abstract: The GAPS experiment is foreseen to carry out a dark matter search using a novel detection approach to detect low-energy cosmic-ray antideuterons. The theoretically predicted antideuteron flux resulting from secondary interactions of primary cosmic rays with the interstellar medium is very low. So far not a single cosmic antideuteron has been detected by any experiment, but well-motivated theories beyond the standard model of particle physics, e.g., supersymmetry or universal extra dimensions, contain viable dark matter candidates, which could led to a significant enhancement of the antideuteron flux due to self-annihilation of the dark matter particles. This flux contribution is believed to be especially large at small energies, which leads to a high discovery potential for GAPS. GAPS is designed to achieve its goals via a series of ultra-long duration balloon flights at high altitude in Antarctica, starting in 2014. The detector itself will consist of 13 planes of Si(Li) solid state detectors and a time of flight system. The low-energy antideuterons (< 0.3 GeV/n) will be slowed down in the Si(Li) material, replace a shell electron, and form an excited exotic atom. The atom will be deexcited by characteristic x-ray transitions and will end its life by forming an annihilation pion star. This unique event structure will allow for nearly background free detection. To prove the performance of the different detector components at stratospheric altitudes, a prototype flight will be conducted in 2011 from Taiki, Japan.