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Zhou RJ. Energy distribution of lost high-energy runaway electrons based on their bremsstrahlung emission in the EAST tokamak. Phys Rev E 2023; 107:045204. [PMID: 37198789 DOI: 10.1103/physreve.107.045204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 04/05/2023] [Indexed: 05/19/2023]
Abstract
We report in this paper the study towards revealing the energy distribution of lost high-energy runaway electrons based on their bremsstrahlung emission. The high-energy hard x-rays are originated from the bremsstrahlung emission of lost runaway electrons in the experimental advanced superconducting tokamak (EAST) tokamak, and the energy spectra are measured using a gamma spectrometer. The energy distribution of the runaway electrons is reconstructed from this hard x-ray energy spectrum using a deconvolution algorithm. The results indicate that the energy distribution of the lost high-energy runaway electrons can be obtained with the deconvolution approach. In the specific case in this paper, the runaway electron energy was peaked around 8 MeV, covering from 6 MeV to 14 MeV.
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Affiliation(s)
- R J Zhou
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
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2
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Lvovskiy A, Paz-Soldan C, Eidietis N, Dal Molin A, Nocente M, Cooper C, Rigamonti D, Tardocchi M, Taussig D. Upgrades to the gamma ray imager on DIII-D enabling access to high flux hard x-ray measurements during the runaway electron plateau phase (invited). THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:113524. [PMID: 36461541 DOI: 10.1063/5.0101690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 09/07/2022] [Indexed: 06/17/2023]
Abstract
The Gamma Ray Imager (GRI) is a pinhole camera providing 2D imaging of MeV hard x-ray (HXR) bremsstrahlung emission from runaway electrons (REs) over the poloidal cross section of the DIII-D tokamak. We report a series of upgrades to the GRI expanding the access to RE scenarios from the diagnosis of a trace amount of REs to high flux HXR measurements during the RE plateau phase. We present the implementation of novel gamma ray detectors based on LYSO and YAP crystals coupled to multi-pixel photon counters, enabling a count rate in excess of 1 MHz. Finally, we highlight new insights into the RE physics discovered during the current quench and RE plateau phase experiments as the result of these upgrades.
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Affiliation(s)
- A Lvovskiy
- General Atomics, P.O. Box 85608, San Diego, California 92186, USA
| | - C Paz-Soldan
- General Atomics, P.O. Box 85608, San Diego, California 92186, USA
| | - N Eidietis
- General Atomics, P.O. Box 85608, San Diego, California 92186, USA
| | - A Dal Molin
- Dipartimento di Fisica, Università degli Studi di Milano-Bicocca, 20126 Milan, Italy
| | - M Nocente
- Dipartimento di Fisica, Università degli Studi di Milano-Bicocca, 20126 Milan, Italy
| | - C Cooper
- Oak Ridge Associated Universities, Oak Ridge, Tennessee 37830, USA
| | - D Rigamonti
- Istituto per la Scienza e Tecnologia dei Plasmi, CNR, 20126 Milan, Italy
| | - M Tardocchi
- Istituto per la Scienza e Tecnologia dei Plasmi, CNR, 20126 Milan, Italy
| | - D Taussig
- General Atomics, P.O. Box 85608, San Diego, California 92186, USA
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3
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Rutherford G, Seltzman AH, Wukitch SJ. Predicted performance of a tangential viewing hard x-ray camera for the DIII-D high field side lower hybrid current drive experiment. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:103529. [PMID: 36319350 DOI: 10.1063/5.0099168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Accepted: 09/07/2022] [Indexed: 06/16/2023]
Abstract
High field side launch of lower hybrid current drive (LHCD) has improved accessibility and penetration over low field side launch on DIII-D. Simulations predict single pass absorption under a wide range of plasma conditions. Hard x-ray (HXR) measurement of LHCD generated fast electron bremsstrahlung (50-250 keV) will validate wave propagation and absorption. Emissivity profiles are recovered from one-dimensional inversion of HXR brightness to determine LH damping location, fast electron slowing down time, and some indication of the fast electron energy. The camera will be implemented by populating 32 tangential sightlines of the existing Gamma Ray Imager with Kromek SPEARTM Cadmium Zinc Telluride (CZT) detectors sensitive to 10-1000 keV photons with 10 keV energy resolution. Expected count rates allow for <0.5 ms time resolution. Pulses are processed using 50 ns shaping time Cremat CR-200 Gaussian shaping modules and are digitized by 25 MHz D-TACQ ACQ216 digitizers. The performance of the HXR camera is evaluated by comparing predicted fast electron density profiles and inverted synthetic brightnesses obtained from the ray-tracing/Fokker-Planck codes GENRAY/CQL3D. Inversions closely matched predicted fast electron profiles for a range of experimental parameters.
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Affiliation(s)
- Grant Rutherford
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA
| | - Andrew H Seltzman
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA
| | - Stephen J Wukitch
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA
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4
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Chen W, Hu L, Zhong G, Hong B, Zhou R, Li K, Huang L, Cao H. Design of the radiation shield and collimator for neutron and gamma-ray diagnostics at EAST. FUSION ENGINEERING AND DESIGN 2021. [DOI: 10.1016/j.fusengdes.2021.112775] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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5
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Dal Molin A, Fumagalli L, Nocente M, Rigamonti D, Tardocchi M, Giacomelli L, Panontin E, Lvovskiy A, Paz-Soldan C, Edietis NW, Gorini G. Novel compact hard x-ray spectrometer with MCps counting rate capabilities for runaway electron measurements on DIII-D. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:043517. [PMID: 34243482 DOI: 10.1063/5.0043762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 03/18/2021] [Indexed: 06/13/2023]
Abstract
A novel compact spectrometer optimized for the measurement of hard x rays generated by runaway electrons is presented. The detector is designed to be installed in the fan-shaped collimator of the gamma-ray imager diagnostic at the DIII-D tokamak. The spectrometer is based on a 1 × 1 cm2 cerium doped yttrium aluminum perovskite scintillator crystal coupled with a silicon photomultiplier. The detector dynamic energy range is in excess of 10 MeV, with an energy resolution of ∼10% at 661.7 keV. The fast detector signal (≈70 ns full width at half maximum) allows for operation at counting rates in excess of 1 MCps. The gain stability of the system can be monitored in real time using a light-emitting diode embedded in the instrument. The detector is expected to be deployed in the forthcoming DIII-D runaway electron experimental campaign.
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Affiliation(s)
- A Dal Molin
- Dipartimento di Fisica, Università degli Studi di Milano-Bicocca, 20126 Milan, Italy
| | - L Fumagalli
- Dipartimento di Fisica, Università degli Studi di Milano-Bicocca, 20126 Milan, Italy
| | - M Nocente
- Dipartimento di Fisica, Università degli Studi di Milano-Bicocca, 20126 Milan, Italy
| | - D Rigamonti
- Istituto per la Scienza e Tecnologia dei Plasmi, CNR, 20126 Milan, Italy
| | - M Tardocchi
- Istituto per la Scienza e Tecnologia dei Plasmi, CNR, 20126 Milan, Italy
| | - L Giacomelli
- Istituto per la Scienza e Tecnologia dei Plasmi, CNR, 20126 Milan, Italy
| | - E Panontin
- Dipartimento di Fisica, Università degli Studi di Milano-Bicocca, 20126 Milan, Italy
| | - A Lvovskiy
- General Atomics, San Diego, California 92127, USA
| | - C Paz-Soldan
- General Atomics, San Diego, California 92127, USA
| | - N W Edietis
- General Atomics, San Diego, California 92127, USA
| | - G Gorini
- Dipartimento di Fisica, Università degli Studi di Milano-Bicocca, 20126 Milan, Italy
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6
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Zhou RJ, Zhong GQ, Hu LQ, Tardocchi M, Rigamonti D, Giacomelli L, Nocente M, Gorini G, Fan TS, Zhang YM, Hu ZM, Xiao M, Li K, Zhang YK, Hong B, Zhang Y, Lin SY, Zhang JZ. Development of gamma ray spectrometer with high energy and time resolutions on EAST tokamak. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2019; 90:123510. [PMID: 31893803 DOI: 10.1063/1.5120843] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2019] [Accepted: 11/22/2019] [Indexed: 06/10/2023]
Abstract
A new gamma ray spectrometer with high energy and time resolutions has been developed and installed on the EAST tokamak to study fast ion and runaway electron behaviors. The spectrometer is based on a LaBr3(Ce) scintillator detector and a fully digital data acquisition system that is based on a digitizer with digital pulse processing algorithms. The energy resolution of the spectrometer is about 3.9% at 662 keV, and the spectrometer can operate stably at a counting rate as high as 1 MHz, monitored by using a light emitting diode monitoring system. The measured gamma ray spectrum is simulated based on Geant4 and unfolded with the high-resolution boosted Gold deconvolution algorithm, aiming at reconstructing the energy distribution functions of fast ions and runaway electrons.
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Affiliation(s)
- R J Zhou
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - G Q Zhong
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - L Q Hu
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - M Tardocchi
- Istituto per la Scienza e Tecnologia dei Plasmi, Consiglio Nazionale delle Ricerche, Milano 20125, Italy
| | - D Rigamonti
- Istituto per la Scienza e Tecnologia dei Plasmi, Consiglio Nazionale delle Ricerche, Milano 20125, Italy
| | - L Giacomelli
- Istituto per la Scienza e Tecnologia dei Plasmi, Consiglio Nazionale delle Ricerche, Milano 20125, Italy
| | - M Nocente
- Istituto per la Scienza e Tecnologia dei Plasmi, Consiglio Nazionale delle Ricerche, Milano 20125, Italy
| | - G Gorini
- Istituto per la Scienza e Tecnologia dei Plasmi, Consiglio Nazionale delle Ricerche, Milano 20125, Italy
| | - T S Fan
- State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China
| | - Y M Zhang
- State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China
| | - Z M Hu
- State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China
| | - M Xiao
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - K Li
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - Y K Zhang
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - B Hong
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - Y Zhang
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - S Y Lin
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - J Z Zhang
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China
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7
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Figueiredo J, Murari A, Perez Von Thun C, Marocco D, Tardocchi M, Belli F, García Muñoz M, Silva A, Craciunescu T, Blanchard P, Balboa I, Hawkes N, Carvalho IS, Tal B, Bernardo J, Zychor I. JET diagnostic enhancements testing and commissioning in preparation for DT scientific campaigns. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:10K119. [PMID: 30399696 DOI: 10.1063/1.5038548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 06/29/2018] [Indexed: 06/08/2023]
Abstract
In order to optimize the scientific exploitation of JET (Joint European Torus) during the upcoming deuterium-tritium experiments, a set of diagnostic systems is being enhanced. These upgrades focus mainly on the experimental and operational conditions expected during tritium campaigns. It should be stressed that measurements relevant for burning plasmas are specifically targeted. Previously non-available capabilities, such as a current measurement system fully covering all poloidal field circuits, are described in detail. Instrument descriptions, performance prediction, testing, and initial commissioning results of these systems are presented.
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Affiliation(s)
- J Figueiredo
- EUROfusion Programme Management Unit, Culham Science Centre, Abingdon, United Kingdom
| | - A Murari
- EUROfusion Programme Management Unit, Culham Science Centre, Abingdon, United Kingdom
| | - C Perez Von Thun
- EUROfusion Programme Management Unit, Culham Science Centre, Abingdon, United Kingdom
| | - D Marocco
- Unità Tecnica Fusione, ENEA C. R. Frascati, Via E. Fermi 45, 00044 Frascati, Roma, Italy
| | - M Tardocchi
- IFP-CNR, Via R. Cozzi 53, 20125 Milano, Italy
| | - F Belli
- Unità Tecnica Fusione, ENEA C. R. Frascati, Via E. Fermi 45, 00044 Frascati, Roma, Italy
| | | | - A Silva
- Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal
| | - T Craciunescu
- The National Institute for Laser, Plasma and Radiation Physics, Magurele, Bucharest, Romania
| | - P Blanchard
- Ecole Polytechnique Fédérale de Lausanne (EPFL), CRPP, CH-1015 Lausanne, Switzerland
| | - I Balboa
- CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom
| | - N Hawkes
- CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom
| | - I S Carvalho
- Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal
| | - B Tal
- Wigner Research Centre for Physics, P.O. Box 49, H-1525 Budapest, Hungary
| | - J Bernardo
- Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal
| | - I Zychor
- Narodowe Centrum Badań Jądrowych (NCBJ), 05-400 Otwock-Swierk, Poland
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8
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Dal Molin A, Martinelli L, Nocente M, Rigamonti D, Abba A, Giacomelli L, Gorini G, Lvovskiy A, Muraro A, Tardocchi M. Development of a new compact gamma-ray spectrometer optimised for runaway electron measurements. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:10I134. [PMID: 30399979 DOI: 10.1063/1.5038803] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Accepted: 06/25/2018] [Indexed: 06/08/2023]
Abstract
A new compact gamma-ray spectrometer was developed in order to optimise the measurement of bremsstrahlung radiation emitted from runaway electrons in the MeV range. The detector is based on a cerium doped lutetium-yttrium oxyorthosilicate (LYSO:Ce) scintillator coupled to a silicon photomultiplier and is insensitive to magnetic fields. A dedicated electronic board was developed to optimise the signal readout as well as for online control of the device. The detector combines a dynamic range up to 10 MeV with moderate energy non-linearity, counting rate capabilities in excess of 1 MHz, and an energy resolution that extrapolates to a few % in the MeV range, thus meeting the requirements for its application to runaway electron studies by bremsstrahlung measurements in the gamma-ray energy range.
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Affiliation(s)
- A Dal Molin
- Dipartimento di Fisica "G. Occhialini," Università degli Studi di Milano-Bicocca, Milano, Italy
| | - L Martinelli
- Dipartimento di Fisica "G. Occhialini," Università degli Studi di Milano-Bicocca, Milano, Italy
| | - M Nocente
- Dipartimento di Fisica "G. Occhialini," Università degli Studi di Milano-Bicocca, Milano, Italy
| | - D Rigamonti
- Istituto di Fisica del Plasma "P. Caldirola," CNR, Milano, Italy
| | - A Abba
- Nuclear Instruments, Lambrugo, Italy
| | - L Giacomelli
- Istituto di Fisica del Plasma "P. Caldirola," CNR, Milano, Italy
| | - G Gorini
- Dipartimento di Fisica "G. Occhialini," Università degli Studi di Milano-Bicocca, Milano, Italy
| | - A Lvovskiy
- Oak Ridge Associated Universities, Oak Ridge, Tennessee 37831, USA
| | - A Muraro
- Istituto di Fisica del Plasma "P. Caldirola," CNR, Milano, Italy
| | - M Tardocchi
- Istituto di Fisica del Plasma "P. Caldirola," CNR, Milano, Italy
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9
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Paz-Soldan C, Cooper CM, Aleynikov P, Pace DC, Eidietis NW, Brennan DP, Granetz RS, Hollmann EM, Liu C, Lvovskiy A, Moyer RA, Shiraki D. Spatiotemporal Evolution of Runaway Electron Momentum Distributions in Tokamaks. PHYSICAL REVIEW LETTERS 2017; 118:255002. [PMID: 28696735 DOI: 10.1103/physrevlett.118.255002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Indexed: 06/07/2023]
Abstract
Novel spatial, temporal, and energetically resolved measurements of bremsstrahlung hard-x-ray (HXR) emission from runaway electron (RE) populations in tokamaks reveal nonmonotonic RE distribution functions whose properties depend on the interplay of electric field acceleration with collisional and synchrotron damping. Measurements are consistent with theoretical predictions of momentum-space attractors that accumulate runaway electrons. RE distribution functions are measured to shift to a higher energy when the synchrotron force is reduced by decreasing the toroidal magnetic field strength. Increasing the collisional damping by increasing the electron density (at a fixed magnetic and electric field) reduces the energy of the nonmonotonic feature and reduces the HXR growth rate at all energies. Higher-energy HXR growth rates extrapolate to zero at the expected threshold electric field for RE sustainment, while low-energy REs are anomalously lost. The compilation of HXR emission from different sight lines into the plasma yields energy and pitch-angle-resolved RE distributions and demonstrates increasing pitch-angle and radial gradients with energy.
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Affiliation(s)
- C Paz-Soldan
- General Atomics, San Diego, California 92186, USA
| | - C M Cooper
- Oak Ridge Associated Universities, Oak Ridge, Tennessee 37831, USA
| | - P Aleynikov
- Max-Planck Institute for Plasma Physics, Greifswald, Germany
| | - D C Pace
- General Atomics, San Diego, California 92186, USA
| | - N W Eidietis
- General Atomics, San Diego, California 92186, USA
| | - D P Brennan
- Princeton University, Princeton, New Jersey 05764, USA
| | - R S Granetz
- Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - E M Hollmann
- University of California-San Diego, La Jolla, California 92093, USA
| | - C Liu
- Princeton University, Princeton, New Jersey 05764, USA
| | - A Lvovskiy
- Oak Ridge Associated Universities, Oak Ridge, Tennessee 37831, USA
| | - R A Moyer
- University of California-San Diego, La Jolla, California 92093, USA
| | - D Shiraki
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
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Cooper CM, Pace DC, Paz-Soldan C, Commaux N, Eidietis NW, Hollmann EM, Shiraki D. Applying the new gamma ray imager diagnostic to measurements of runaway electron Bremsstrahlung radiation in the DIII-D Tokamak (invited). THE REVIEW OF SCIENTIFIC INSTRUMENTS 2016; 87:11E602. [PMID: 27910457 DOI: 10.1063/1.4961288] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
A new gamma ray imager (GRI) is developed to probe the electron distribution function with 2D spatial resolution during runaway electron (RE) experiments at the DIII-D tokamak. The diagnostic is sensitive to 0.5-100 MeV gamma rays, allowing characterization of the RE distribution function evolution during RE growth and dissipation. The GRI consists of a lead "pinhole camera" mounted on the DIII-D midplane with 123 honeycombed tangential chords 20 cm wide that span the vessel interior. Up to 30 bismuth germanate (BGO) scintillation detectors capture RE bremsstrahlung radiation for Pulse Height Analysis (PHA) capable of discriminating up to 20 000 pulses per second. Digital signal processing routines combining shaping filters are performed during PHA to reject noise and record gamma ray energy. The GRI setup and PHA algorithms will be described and initial data from experiments will be presented. A synthetic diagnostic is developed to generate the gamma ray spectrum of a GRI channel given the plasma information and a prescribed distribution function. Magnetic reconstructions of the plasma are used to calculate the angle between every GRI sightline and orient and discriminate gamma rays emitted by a field-aligned RE distribution function.
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Affiliation(s)
- C M Cooper
- Oak Ridge Associated Universities, Oak Ridge, Tennessee 37830, USA
| | - D C Pace
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608, USA
| | - C Paz-Soldan
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608, USA
| | - N Commaux
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA
| | - N W Eidietis
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608, USA
| | - E M Hollmann
- University of California, San Diego, La Jolla, California 92093-0533, USA
| | - D Shiraki
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA
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