| 1. |
- Abdo, A. A., et al.
(författare)
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The Fermi Gamma-Ray Space Telescope Discovers the Pulsar in the Young Galactic Supernova Remnant CTA 1
- 2008
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 322:5905, s. 1218-1221
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Tidskriftsartikel (refereegranskat)abstract
- Energetic young pulsars and expanding blast waves [ supernova remnants (SNRs)] are the most visible remains after massive stars, ending their lives, explode in core-collapse supernovae. The Fermi Gamma- Ray Space Telescope has unveiled a radio quiet pulsar located near the center of the compact synchrotron nebula inside the supernova remnant CTA 1. The pulsar, discovered through its gamma- ray pulsations, has a period of 316.86 milliseconds and a period derivative of 3.614 x 10(-13) seconds per second. Its characteristic age of 10(4) years is comparable to that estimated for the SNR. We speculate that most unidentified Galactic gamma- ray sources associated with star- forming regions and SNRs are such young pulsars.
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| 2. |
- Yamada, Y., et al.
(författare)
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Antidazzle effect of switchable mirrors prepared on substrates with rough surface
- 2008
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Ingår i: Solar Energy Materials and Solar Cells. - : Elsevier BV. - 0927-0248 .- 1879-3398. ; 92:12, s. 1617-1620
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Tidskriftsartikel (refereegranskat)abstract
- To examine the antidazzle effect of switchable mirrors, mirrors based on a magnesium-nickel alloy were prepared on three kinds of transparent substrates with different surface roughness. The mirrors prepared using a direct-current magnetron sputtering method have nearly the same surface morphology and roughness as the underlying substrates. The diffuse fraction of the total reflectance of the mirrors increases with surface roughness of the mirrors. Thus. by utilizing substrates with rough surfaces, the specular reflectance of the mirrors decreases and consequently it is possible to prepare switchable mirrors with an antidazzle effect.
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| 3. |
- Yamada, Y., et al.
(författare)
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Optical properties of tungsten oxide thin films with protons intercalated during sputtering
- 2008
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 103:6, s. 063508-063508-4
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Tidskriftsartikel (refereegranskat)abstract
- Tungsten oxide thin films with protons intercalated during deposition (HxWO3) were prepared using reactive direct-current-magnetron sputtering in a gas mixture of argon, oxygen, and hydrogen. The as-deposited films fabricated under suitable conditions were colored due to the formation of tungsten bronze. The concentration of intercalated protons, given by the x values in HxWO(3), was evaluated by ejecting protons electrochemically from the films. The x value of the films prepared at a constant working pressure was found to be proportional to the hydrogen flow ratio during deposition. On the other hand, the x value of the films prepared at a constant hydrogen flow ratio decreased sharply with increasing working pressure during deposition. The dispersion of the extinction coefficient (kappa) of the films was estimated by analyzing the experimental spectra of psi and Delta measured with spectroscopic ellipsometry using the model composed of a homogeneous tungsten bronze layer with an additional surface roughness layer. As a result of this analysis, the kappa value was found to increase sharply with the number of intercalated protons. There was a linear dependence between the kappa value and the x value for x 0.2, while for x 0.3, the absorption saturated. This indicates that it is possible to evaluate the x value of HxWO3 films using spectroscopic ellipsometry.
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| 4. |
- Kiss, Mózsi, et al.
(författare)
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The PoGOLite balloon-borne soft gamma-ray polarimeter
- 2008
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Ingår i: COOL DISCS, HOT FLOWS. - : AIP. ; , s. 225-232
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Konferensbidrag (refereegranskat)abstract
- Linearly polarized radiation in the hard X-ray/soft gamma-ray band is expected from a large variety of astronomical sources. We discuss the importance of polarimetric studies for several classes of sources - pulsars, accreting black holes. magnetic neutron stars and jets from active galaxies - and then describe PoGOLite, a balloon-borne instrument which is currently under construction and will be able to measure the polarization of electromagnetic radiation from such extra-solar objects in the energy range 25-80 keV.
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| 5. |
- Takahashi, H., et al.
(författare)
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Beam test results of the polarized gamma-ray observer, PoGOLite
- 2008
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Ingår i: 2008 IEEE NUCLEAR SCIENCE SYMPOSIUM AND MEDICAL IMAGING CONFERENCE (2008 NSS/MIC), VOLS 1-9. - 9781424427147 ; , s. 732-736
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Konferensbidrag (refereegranskat)abstract
- The Polarized Gamma-ray Observer, PoGOLite, is a balloon experiment with the capability of detecting 10% polarization from a 200 mCrab celestial object in the energy range 25 #x2013;80 keV. During a beam test at KEK-PF in February 2008, 20 detector units were assembled, and a 50 keV X-ray beam with a polarization degree of #x223C;90% was irradiated at the center unit. Signals from all 20 units were fed into flightversion electronics consisting of six circuit boards (four waveform digitizer boards, one digital I/O board and one router board) and one microprocessor (SpaceCube), which communicate using a SpaceWire interface. One digitizer board, which can associate up to 8 PDCs, outputs a trigger signal. The digital I/O board handles the trigger and returns a data acquisition request if there is no veto signal (upper or pulse-shape discriminators) from any detector unit. This data acquisition system worked well, and the modulation factor was successfully measured to be #x223C;34%. These results confirmed the capabilities of both detector and data-acquisition system for a pathfinder flight planned in 2010.
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