14,794 research outputs found
Soft Gamma-ray Detector for the ASTRO-H Mission
ASTRO-H is the next generation JAXA X-ray satellite, intended to carry
instruments with broad energy coverage and exquisite energy resolution. The
Soft Gamma-ray Detector (SGD) is one of ASTRO-H instruments and will feature
wide energy band (40-600 keV) at a background level 10 times better than the
current instruments on orbit. SGD is complimentary to ASTRO-H's Hard X-ray
Imager covering the energy range of 5-80 keV. The SGD achieves low background
by combining a Compton camera scheme with a narrow field-of-view active shield
where Compton kinematics is utilized to reject backgrounds. The Compton camera
in the SGD is realized as a hybrid semiconductor detector system which consists
of silicon and CdTe (cadmium telluride) sensors. Good energy resolution is
afforded by semiconductor sensors, and it results in good background rejection
capability due to better constraints on Compton kinematics. Utilization of
Compton kinematics also makes the SGD sensitive to the gamma-ray polarization,
opening up a new window to study properties of gamma-ray emission processes.
The ASTRO-H mission is approved by ISAS/JAXA to proceed to a detailed design
phase with an expected launch in 2014. In this paper, we present science
drivers and concept of the SGD instrument followed by detailed description of
the instrument and expected performance.Comment: 17 pages, 15 figures, Proceedings of the SPIE Astronomical
Instrumentation "Space Telescopes and Instrumentation 2010: Ultraviolet to
Gamma Ray
Light-sheet microscopy: a tutorial
This paper is intended to give a comprehensive review of light-sheet (LS) microscopy from an optics perspective. As such, emphasis is placed on the advantages that LS microscope configurations present, given the degree of freedom gained by uncoupling the excitation and detection arms. The new imaging properties are first highlighted in terms of optical parameters and how these have enabled several biomedical applications. Then, the basics are presented for understanding how a LS microscope works. This is followed by a presentation of a tutorial for LS microscope designs, each working at different resolutions and for different applications. Then, based on a numerical Fourier analysis and given the multiple possibilities for generating the LS in the microscope (using Gaussian, Bessel, and Airy beams in the linear and nonlinear regimes), a systematic comparison of their optical performance is presented. Finally, based on advances in optics and photonics, the novel optical implementations possible in a LS microscope are highlighted.Peer ReviewedPostprint (published version
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