14,203 research outputs found
Novel Multi-pixel Silicon Photon Detectors and Applications in T2K
Nowadays, numerous fields such as High Energy Physics (HEP), medical imaging
devices, portable radiation detectors etc., require a robust, miniature,
reliable and readily available photon detector that is stable in a variety of
environments, such as the presence of strong magnetic fields. The recently
available 1mm active area Multi-pixel Photon Counter
(MPPC) sensors, produced by Hamamatsu Photonics, have been found to be reliable
and an attractive choice for the HEP applications.
The following sensor characteristics have been thoroughly tested by T2K
collaboration: gain, dark noise, detection efficiency, reliability. These
appear to be stable; in addition, the characteristic spread between numerous
devices was assessed. Sensors with larger area are being developed for imaging
and direct-to-scintillator coupling purposes.Comment: To be published in the proceedings of DPF-2009, Detroit, MI, July
2009, eConf C09072
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
Enhancing fluorescence excitation and collection from the nitrogen-vacancy center in diamond through a micro-concave mirror
We experimentally demonstrate a simple and robust optical fibers based method
to achieve simultaneously efficient excitation and fluorescence collection from
Nitrogen-Vacancy (NV) defects containing micro-crystalline diamond. We
fabricate a suitable micro-concave (MC) mirror that focuses scattered
excitation laser light into the diamond located at the focal point of the
mirror. At the same instance, the mirror also couples the fluorescence light
exiting out of the diamond crystal in the opposite direction of the optical
fiber back into the optical fiber within its light acceptance cone. This part
of fluorescence would have been otherwise lost from reaching the detector. Our
proof-of-principle demonstration achieves a 25 times improvement in
fluorescence collection compared to the case of not using any mirrors. The
increase in light collection favors getting high signal-to-noise ratio (SNR)
optically detected magnetic resonance (ODMR) signals hence offers a practical
advantage in fiber-based NV quantum sensors. Additionally, we compacted the NV
sensor system by replacing some bulky optical elements in the optical path with
a 1x2 fiber optical coupler in our optical system. This reduces the complexity
of the system and provides portability and robustness needed for applications
like magnetic endoscopy and remote-magnetic sensing.Comment: 6 pages, 8 figure
Spaceborne sensors (1983-2000 AD): A forecast of technology
A technical review and forecast of space technology as it applies to spaceborne sensors for future NASA missions is presented. A format for categorization of sensor systems covering the entire electromagnetic spectrum, including particles and fields is developed. Major generic sensor systems are related to their subsystems, components, and to basic research and development. General supporting technologies such as cryogenics, optical design, and data processing electronics are addressed where appropriate. The dependence of many classes of instruments on common components, basic R&D and support technologies is also illustrated. A forecast of important system designs and instrument and component performance parameters is provided for the 1983-2000 AD time frame. Some insight into the scientific and applications capabilities and goals of the sensor systems is also given
Multichannel optical atomic magnetometer operating in unshielded environment
A multi-channel atomic magnetometer operating in an unshielded environment is
described and characterised. The magnetometer is based on D1 optical pumping
and D2 polarimetry of Cs vapour contained in gas-buffered cells. Several
technical implementations are described and discussed in detail. The
demonstrated sensitivity of the setup is 100fT/Hz^1/2 when operating in the
difference mode.Comment: 9 pages, 5 figures, appearing in Appl.Phys.
NASA SBIR abstracts of 1991 phase 1 projects
The objectives of 301 projects placed under contract by the Small Business Innovation Research (SBIR) program of the National Aeronautics and Space Administration (NASA) are described. These projects were selected competitively from among proposals submitted to NASA in response to the 1991 SBIR Program Solicitation. The basic document consists of edited, non-proprietary abstracts of the winning proposals submitted by small businesses. The abstracts are presented under the 15 technical topics within which Phase 1 proposals were solicited. Each project was assigned a sequential identifying number from 001 to 301, in order of its appearance in the body of the report. Appendixes to provide additional information about the SBIR program and permit cross-reference of the 1991 Phase 1 projects by company name, location by state, principal investigator, NASA Field Center responsible for management of each project, and NASA contract number are included
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