| 1. |
- Kiss, Mózsi Bank, et al.
(author)
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PoGOLite : Opening a new window on the universe with polarized gamma-rays
- 2007
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In: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 580:2, s. 876-879
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Journal article (peer-reviewed)abstract
- PoGOLite (the Polarized Gamma-ray Observer, light-weight version) is a balloon-borne instrument that will measure the polarization of soft gamma-rays in the energy range 25-100keV from various astronomical sources such as pulsars, active galactic nuclei, galactic X-ray binaries and accreting black holes. The polarization properties of such radiation can reveal important new information about the geometry, magnetic fields and the emission mechanisms of the observed sources. The first flight is scheduled for 2009. In this paper, we present the current state of the project.
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| 2. |
- Marini Bettolo, Cecilia, et al.
(author)
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The BGO anticoincidence system of the PoGOLite balloon-borne soft gamma-ray polarimeter
- 2007
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In: Proceedings of the 30th International Cosmic Ray Conference, ICRC 2007. - : Universidad Nacional Autonoma de Mexico. ; , s. 483-486
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Conference paper (peer-reviewed)abstract
- The PoGOLite balloon-borne experiment applies well-type phoswich detector technology tomeasurements of soft gamma-ray polarization in the 25 keV - 80 keV energy range. The polarization isdetermined using Compton scattering and photoelectric absorption in an array of 217 plastic scintillators.This sensitive volume is surrounded by a segmented bismuth germanate oxide (BGO) anticoincidenceshield, designed to reduce background from charged cosmic rays, primary and atmospheric gamma-rays,and atmospheric and instrumental neutrons. A total of 379 BGO crystals with three different geometriesare used, giving an overall mass of approximately 250 kg. Tests of the BGO crystals are described andthe overall design of the anticoincidence shield is reviewed.
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| 3. |
- Mizuno, T., et al.
(author)
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High sensitivity balloon-borne hard X-ray/soft Gamma-Ray Polarimeter PoGOLite
- 2007
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In: Nuclear Science Symposium Conference Record, 2007. NSS ’07. IEEE. - : IEEE. - 9781424409228 ; , s. 2538-2544
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Conference paper (peer-reviewed)abstract
- The Polarized Gamma-ray Observer - Lightweight version (PoGOLite) is a new balloon experiment capable of detecting 10% polarization from a 200 mCrab source in the 25-80 keV energy range in a single 6-hour flight for the first time. Polarization measurements of hard X-rays and soft gamma-rays are expected to provide a powerful probe into high-energy emission mechanisms as well as source geometries. PoGOLite uses Compton scattering and photo-absorption to measure polarization in an array of 217 well-type phoswich detector cells made of plastic and BGO scintillators. The adoption of a well-type phoswich counter concept and a thick polyethylene neutron shield provides a narrow field-of-view (1.25 msr), a large effective area ( gt; 250 cm2 at 40-50 keV), a high modulation factor (more than 25%) and the low background ( 100 mCrab) required to conduct high-sensitivity polarization measurements. Through tests in laboratories and accelerator facilities of a scaled-down prototype with the front-end electronics of flight design and an extensive study by Monte Carlo simulation, we have demonstrated high instrument performance. PoGOLite will be ready for a first engineering flight in 2009 and a science flight in 2010, during which polarization signals from the Crab Nebula/pulsar, Cygnus X-1 and other objects will be observed.
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| 4. |
- Takahashi, H., et al.
(author)
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A thermal-neutron detector with a phoswich system of LiCaAlF6 and BGO crystal scintillators onboard PoGOLite
- 2010
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In: 2010 IEEE Nuclear Science Symposium, Medical Imaging Conference, NSS/MIC 2010 and 17th International Workshop on Room-Temperature Semiconductor X-ray and Gamma-ray Detectors, RTSD 2010. ; , s. 32-37
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Conference paper (peer-reviewed)abstract
- To measure the flux of atmospheric neutrons and study the neutron contribution to the background of the main detector of the PoGOLite (Polarized Gamma-ray Observer) balloon-borne experiment, a thermal-neutron detector with a phoswich system of LiCaAlF6 (Eu) and BGO crystal scintillators is developed. The performance to separate thermal-neutron events from those of gamma-rays and charged particles is validated with 252Cf on ground. The detector is attached to the PoGOLite instrument and is launched in 2011 from the Esrange facility in the North of Sweden. Although the emission wavelength of the LiCaAlF6 (Ce) is 300 nm and overlaps with the absorption wavelength of the BGO, the phoswich capability of the LiCaAlF6 (Ce) with the BGO is also confirmed with installing a waveform shifter.
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| 5. |
- Takahashi, H., et al.
(author)
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Beam test results of the polarized gamma-ray observer, PoGOLite
- 2008
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In: 2008 IEEE NUCLEAR SCIENCE SYMPOSIUM AND MEDICAL IMAGING CONFERENCE (2008 NSS/MIC), VOLS 1-9. - 9781424427147 ; , s. 732-736
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Conference paper (peer-reviewed)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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| 6. |
- Takahashi, H., et al.
(author)
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The Polarized Gamma-Ray Observer, PoGOLite
- 2010
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In: Transactions of the Japanese Society for Artificial Intelligence, Aerospace Technology Japan. - 1346-0714 .- 1346-0714. ; 8
-
Journal article (peer-reviewed)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 25–80 keV. During a beam test at KEK-PF in 2008, 19 detector units and one anti-coincidence detector were assembled, and a 50 keV X-ray beam with a polarization degree of ∼90% was irradiated at the center unit. Signals from all 20 units were fed into flight-version 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 detectors, 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 ∼34%. These results confirmed the capabilities of the data-acquisition system for a “pathfinder” flight planned in 2010.
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