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Peterson, B. J.*; Alekseyev, A. G.*; Konoshima, Shigeru; Ashikawa, Naoko*; Parchamy, H.*; Sasao, Mamiko*; Miura, Yukitoshi
no journal, ,
The imaging bolometer concept is based on a thin foil which absorbs the broad-band radiation and/or energetic particles from the plasma. The resulting temperature change in the foil is measured by an infrared camera located outside the vacuum vessel. Development of imaging bolometers is being carried out for application in bolometry and lost alpha diagnosis for fusion reactors. In the case of an imaging bolometer, placing the foil behind a pinhole camera provides a two-dimensional image of the plasma radiation. In the case of a lost alpha diagnostic the foil is placed behind multiple layers of thin foils with one dimension being used for energy discrimination and the other layer being used for pitch angle discrimination. The work described includes the operation of imaging bolometers on the Large Helical Device and the JT-60U Tokamak, calibration experiments, testing prototype lost alpha diagnostic detectors on an ion beam facility and the design of an imaging bolometer and a lost alpha diagnostic for ITER.
Peterson, B. J.*; Alekseyev, A. G.*; Konoshima, Shigeru; Ashikawa, Naoko*; Parchamy, H.*; Sasao, Mamiko*; Isobe, Mitsutaka*; Miura, Yukitoshi
no journal, ,
The confinement of alpha particles is an important topic for the operation of a fusion reactor as they should transfer their energy to the fuel plasma and then be exhausted safely through the divertor. If their confinement is poor they could escape through the last closed flux surface and scrape off layer in a spatially localized manner that could do serious damage to the first wall. Therefore the diagnosis of lost alpha particles is important for the operational safety and evaluation of an experimental fusion reactor. A diagnostic device has been proposed based on an imaging bolometer and a multi-foil thermal detector. In this paper we discuss ongoing work with testing prototype imaging bolometers on LHD and JT-60U, calibration work using a laser heat source, the testing of a prototype multi-foil thermal detector on an ion accelerator and the design of a diagnostic for ITER. This work is partly supported by Grants-in-Aid for Scientific Research of the JSPS, Nos.16560729 and 16082207.