The gammaray polarimeter experiment grape is a concept for an astronomical hard xray compton polarimeter operating in the 50 500 kev energy band. From 1982 to 2002, he worked on the burst and transient source experiment batse on the compton gamma ray observatory, first as mission operations software development manager and, from 1994, as. Maximum likelihood compton polarimetry with the compton. Investigation via polarimetry and spectroscopy grips telescope greiner et. Introduction the gamma ray polarimeter experiment grape is a scintillatorbased compton polarimeter designed to observe polarized astrophysical phenomena in the hard x ray energy band 50 500 kev. X ray polarimetry motivation the photoelectric effect is a promising basis for sensitive x ray polarimeters. So in 1991, nasa launched the compton gamma ray observatory, cgro. It detected 621 events attributable to cosmic gamma rays. An incident gamma ray compton scatters by an angle in one layer of the tracker, transferring energy e 1 to an electron. The compton gamma ray observatory was launched april 7, 1991 and observed the highenergy universe until june 4, 2000 when it safely deorbited and burned up in the earths atmosphere. A combined compton and codedaperture telescope for medium. The astronomy and astrophysics decadal survey thematic science area.
During its high energy astronomy observatory program in 1977, nasa announced plans to build a great observatory for gamma ray astronomy. The gamma ray imagerpolarimeter for solar flares grips albert y. An advanced compton telescope act is being investigated to address the promising science offered in this spectral band. Astrophysical polarization measurements in the soft gammaray band are becoming more feasible as detectors with high position and energy resolution are deployed. The past decade has seen several attempts to measure the xraygammaray polarization of grbs. Gamma ray astronomy, study of astronomical objects and phenomena that emit gamma rays. Among the top priorities for highenergy astronomy in the coming decade are sensitive surveys in the hard x ray soft \ gamma ray 10600 kev and mediumenergy \ gamma ray 0. Polarimetry at high energies international space science institute. Imaging polarimeter for a submev gammaray allsky survey. Compton polarimeter operating in the 50 500 kev energy band.
Following these early discoveries, x ray and gamma ray detectors were carried on many satellites. Compton gamma ray observatory united states satellite. Aug 01, 2005 the compton observatory has a diverse scientific agenda, which includes studies of very energetic celestial phenomena. Several satellite observatories dedicated to x ray and gamma ray astronomy and carrying. Pdf measurement of circular polarization of gammarays with position. X ray polarimetry promises to give qualitatively new information about highenergy astrophysical sources, such as binary black hole systems, microquasars, active galactic nuclei, and gamma ray. A portable neutron spectroscope nspect for detection, imaging and. A future mission in mediumenergy gammaray astrophysics would allow for.
Gamma ray astronomy is directly related to x ray astronomy, and the boundary between them is highly arbitrary. Compton polarimetry in gammaray astronomy springerlink. Developing a compton polarimeter to measure polarization. An x ray or gamma ray polarimeter with both a moderate sensitivity and a wide fov is required. From 1982 to 2002, he worked on the burst and transient source experiment batse on the compton gammaray observatory, first as mission operations software development manager and, from 1994, as coinvestigator. Significant gamma ray emission from our galaxy was first detected in 1967 by the the gamma ray detector aboard the oso3 satellite. Compton, at 17 tons, was the heaviest astrophysical payload ever flown at the time of its launch on april 5, 1991 aboard the space shuttle atlantis. Following 14 years of effort, the observatory was launched from space shuttle. Amman g, tadayuki takahashi h asolar physics laboratory, nasa goddard space flight center, greenbelt, md 20770, usa. So gamma ray astronomy could not develop until it was possible to get our detectors above all or most of the atmosphere, using balloons or spacecraft. In operation from 1991 to 1999, it was named in honour of arthur holly compton. Nasa, compton gamma ray observatory science support center. Future mev gamma ray science and missions aps april, 2015 compton scatter polarimetry 8 paolo soffitta the extreme and variable high energy sky chia laguna 1921092011.
Gamma ray telescopes are designed to observe highenergy astrophysical systems, including stellar coronas, white dwarf stars, neutron stars, black holes, supernova remnants, clusters of galaxies, and diffuse. It is generally customary to include in gamma ray astronomy investigations in the spectral region, where the energy of the quanta exceeds 30 kev corresponding to. The observatory featured four main telescopes in one spacecraft, covering xrays and gamma rays, including various specialized subinstruments and detectors. The gamma ray polarimeter experiment grape is a concept for an astronomical hard x ray compton polarimeter operating in the 50 500 kev energy band. In the energy range from a few hundreds of kev to a few tens of mev, compton cameras have been studied as gamma ray imaging telescopes capable of polarimetry and wide fov. It is generally customary to include in gamma ray astronomy investigations in the spectral region, where the energy of the quanta exceeds 30 kev corresponding to a wavelength of less than 0. For nine years, compton has hovered in orbit, reliably scanning the galaxy for gamma rays. X ray and gamma ray polarimetry white paper submission to astro 2010. The instrument has been optimized for widefield polarization measurements of transient outbursts from energetic astrophysical objects such as gammaray bursts and solar flares. Gammaray polarimetry polarimetry is potentially valuable tool to supplement imaging, spectroscopy, and timing in highenergy astronomy practically all highenergy astrophysical emission mechanisms should produce linearly polarized radiation. Analysis of the data from compton xray polarimeters which measure the azimuthal and polar scattering angles.
The compton spectrometer and imager cosi is a balloonborne soft gammaray telescope 0. The compton spectrometer and imager cosi is a balloonborne soft gamma ray telescope 0. On april 5, 1991, the compton gamma ray observatory cgro, was launched aboard the space shuttle atlantis from kennedy space center. The astronomy and astrophysics decadal survey, science white papers, no. The compton gamma ray observatory cgro was the most massive instrument ever launched by a nasa space shuttle and continues to revolutionize gamma ray astronomy. The data written in the event files is analyzed using the root software package. The experiment supports the largearea telescope lat in its observations of gamma ray bursts and follows in the tracks of cgro batse in observations of pulsars, terrestrial gamma ray flashes, soft gamma repeaters, solar flares, and any. Grips is part of the nasa heliophysics low cost access to space program and will provide a nearoptimal combination of highresolution imaging, spectroscopy, and polarimetry. A key element of this investigation is the development of a general set of tools to simulate the background environment for a. A fast scintillator compton telescope for mediumenergy gamma ray astronomy. Gamma ray astronomy is the astronomical observation of gamma rays, the most energetic form of electromagnetic radiation, with photon energies above 100 kev.
The compton gamma ray observatory cgro was the second of the nasa great observatories to be launched to space, following the hubble space telescope. A portable neutron spectroscope nspect for detection, imaging and identification of nuclear material. Compton had four instruments that covered an unprecedented six decades of the. Overview of xray polarimetry with time projection chambers. The first gamma ray telescope carried into orbit, on the explorer 11 satellite in 1961, picked up fewer than 100 cosmic gamma ray photons. It is the dominant x ray interaction mechanism below 100 kev in almost all materials and is highly sensitive to polarization. It is an open source software package that was designed for use with gammaray. The balloonborne gammaray imagerpolarimeter for solar flares grips instrument is the next step in studying highenergy ion and electron acceleration in solar flares.
The scattered photon is then absorbed in the calorimeter, depositing energy e 2, and the scattering angle is given by cos mec 2 e 2. They are all based on one or more of the three basic photon interaction mechanisms. The compton observatory has a diverse scientific agenda, which includes studies of very energetic celestial phenomena. Prompt emission polarimetry of gammaray bursts with the. The large area imaging compton telescope comptel schonfelder et al.
We constructed a simulation software with a detailed geometrical model of. However, the imaging compton telescope comtepl schoenfelder et al. Pdf maximum likelihood compton polarimetry with the. Each x ray absorbed in the active gas volume between the gem and the drift electrode produces a photoelectron, which is emitted preferentially in a plane normal to the gem with a sin 2. On these types of compton cameras, only the medium energy gamma ray astronomy telescope mega succeeded the demonstration of gamma ray imaging polarimetry for onaxis incidence of 100% polarized pencil beams at different energies 0. In the energy range from a few hundreds ofkev to a few tens ofmev, compton cameras have been studied as gamma ray imaging spectroscopic telescopes capable of polarimetry and wide fov. Future mev gamma ray science and missions aps april, 2015 future outlook 17 it is not yet clear what the next major steps in spacebased gamma ray astronomy will be. Stars and stellar evolution february 15, 2009 contact dr. Detection techniques in xray and gammaray astronomy 2. Previous work has shown that the minimum detectable polarization mdp of an ideal compton polarimeter can.
The compton gamma ray observatory was launched aboard the space shuttle atlantis in april 1991. Gammaray astronomy article about gammaray astronomy by. Compton was safely deorbited and reentered the earths atmosphere on june 4, 2000. Calibration of the gammaray polarimeter experiment grape. Comptonpair production space telescope compair for. Apr 12, 2019 in 1977, nasa announced plans to build a great observatory for gammaray astronomy. Sep 15, 2017 the compton spectrometer and imager cosi is a medium energy gamma ray 0. Xray and gammaray polarimetry in astronomy is widely viewed as a new probe. Comptonpair production space telescope compair for mev. Radiation below 100 kev is classified as xrays and is the subject of x ray astronomy in most known cases, gamma rays from solar flares and earths atmosphere are generated in the mev range, but it is now known that gamma rays in the gev. On the unfortunate side, astronomers on earth cant see or detect gamma radiation. The mission of cgro was to study gamma ray emissions in not only our galaxy, but other galaxies beyond ours.
The instrument has been optimized for widefield polarization measurements of transient outbursts from energetic astrophysical objects such as gamma ray bursts and solar flares. Compton polarimetry with a multilayer cdte focal plane. Gamma ray astronomy history of gamma ray astronomy long before experiments could detect gamma rays emitted by cosmic sources, scientists had known that the universe should be producing these photons. Previous work has shown that the minimum detectable polarization mdp of an ideal compton polarimeter can be improved by. Xray polarimetry by means of compton scattering in the. Work by feenberg and primakoff in 1948, hayakawa and hutchinson in 1952, and morrison in 1958 had led scientists to believe that a number of different processes occurring in. Mev gev above 50 gev there are so few gamma rays that satellite detectors, area m2, are too small. Gamma rays with energy below 50 are detected in space using the compton effect. The compton gamma ray observatory cgro was a space observatory detecting photons with energies from 20 kev to 30 gev, in earth orbit from 1991 to 2000. Imaging polarimeter for a submev gamma ray allsky survey using an electrontracking compton camera. However, the field of gamma ray astronomy took great leaps forward with the sas2 1972 and the cosb 19751982 satellites. The compton spectrometer and imager cosi is a medium energy gamma ray 0. The basic principle of the compton mode of operation is illustrated in figure 2, left.
Calibration of the gammaray polarimeter experiment. You need an ereader or compatible software to experience the. Analysis of the data from compton x ray polarimeters which measure the azimuthal and polar scattering angles. Compton polarimetry has long been used in the field of nuclear gammaray. Alsoread articles reads history translate this page. Dfg within the emmy noether program under contract no.
Pdf maximum likelihood compton polarimetry with the compton. X ray, gamma ray, scintillator, astronomy, compton, polarimetry, balloon 1. This orbiting observatory sees the sky in gamma ray photons light. The experiment supports the largearea telescope lat in its observations of gamma ray bursts and follows in the tracks of cgro batse in observations of pulsars, terrestrial gamma ray flashes, soft gamma repeaters, solar flares, and any high energy. The operational principle behind all generations of nuclear gamma ray polarimeters has been to measure the asymmetry in the azimuthal distribution of the scattered photons. Astrophysical polarization measurements in the soft gamma ray band are becoming more feasible as detectors with high position and energy resolution are deployed. Compton scattering from proton rhic the crosssection for compton scattering from protons is small.
Compton polarimetry has long been used in the field of nuclear gamma ray spectroscopy in the laboratory. Before compton loses more stabilizing gyroscopes, nasa is considering firing onboard rockets to bring it on a controlled reentry into the ocean. In addition, it was to investigate how neutron stars and black holes change over time. The advantage of the choice of hybrid photon counting detector technology for polarimetry in x ray astronomy lies in measurements in the energy range between 40 and 100 kev, where the exploitation of compton scattering is only possible with the dense pixelation of a sensor. Mega is the prototype of a future telescope for medium energy gamma ray astronomy in the energy range between 400 kev and 50 mev a megalike telescope could be an essential component of the next generation fleet of highenergy astrophysics satellite observatories, filling the gap between hard xrays lowenergy gamma rays integral, astroh and highenergy gamma ray missions. Calibration of the gammaray polarimeter experiment arxiv. Gamma ray astronomy article about gamma ray astronomy by. The compton gamma ray observatory was the second of nasas great observatories. Gamma ray burst monitor the gamma ray burst monitor gbm is the secondary instrument on the fermi gamma ray space telescope formerly glast. Its a good thing it does gamma radiation is highly dangerous to living things. August 11, 1995 the compton gamma ray observatory credit. Basis for compton polarimetry the scattering of a photon off an electron the cross section for this interaction depends on the relative alignment of the spins of the two interacting particles 11720 uspas jan 20 4 individual electrons, moving along the zaxis with an energy e. A clear gamma ray image based on a wellde ned point spread function psf.
Gamma rays coming from space are mostly absorbed by the earths atmosphere. The gammaray imagerpolarimeter for solar flares grips. Gamma ray polarimetry polarimetry is potentially valuable tool to supplement imaging, spectroscopy, and timing in highenergy astronomy practically all highenergy astrophysical emission mechanisms should produce linearly polarized radiation. The compton gamma ray observatory cgro was the most massive instrument ever launched by a nasa space shuttle in 1991 and continues to revolutionize gamma ray astronomy. Abstract not available bibtex entry for this abstract preferred format for this abstract see preferences. Xray and gammaray polarimetry in astronomy is widely viewed as a new probe for. The compton gamma ray observatory cgro was designed to take advantage of the major advances in detector technology during the 1980s, and was launched in 1991. The compton gammaray observatory cgro was designed to take advantage of the major advances in detector technology during the 1980s, and was launched in 1991. Gamma ray telescopes are designed to observe highenergy astrophysical systems, including stellar coronas, white dwarf stars, neutron stars, black holes, supernova remnants, clusters of galaxies, and diffuse gamma ray background radiation found along the plane of the milky way galaxy. Pdf circular polarimetry with gammaray tracking detectors. A compact compton telescope design is employed by cosi to utilize novel tech.
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