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Estimation of Effective Responsivity of AXUV Bolometer in ADITYA Tokamak by Spectrally Resolved Radiation Power Measurement

Kumudni TAHILIANI, Ratneshwar JHA, Prabhat KUMAR and ADITYA Team

Institute for Plasma Research, Bhat, Gandhinagar-382428, India

(Received 9 December 2012 / Accepted 22 July 2013 / Published 15 November 2013)

Abstract

The radiation emission from ADITYA Tokamak is routinely measured using AXUV bolometers [K. Tahiliani et al., Plasma Phys. Control. Fusion 51, 085004 (2009)] and the total radiation power loss is estimated from these measurements assuming constant responsivity. This assumption is valid for the current flattop phase of the discharge, where the contribution from long wavelength radiation (> 620 Å) is expected to be small and the AXUV responsivity is almost constant. It is likely that in disruptive discharges, with significant edge radiation, a part of the unaccounted power is in the long wavelength range. A better approach is to experimentally determine an effective responsivity by spectrally resolving the radiation power loss and assigning appropriate weights to spectral ranges [S.D. Gray et al., Rev. Sci. Instrum. 75, 376 (2004)]. For this purpose, we have installed a multichannel filtered bolometer camera in ADITYA Tokamak. The wide angle view camera houses three single channel AXUV bolometers, of which two view the plasma through different ultraviolet filters and one has an unfiltered view. All the bolometers have the same poloidal view and are located adjacently in the toroidal direction. The initial results of the spectrally resolved bolometer measurements show that the radiation in the spectral range > 1200 Å is significant fraction of the total radiation during the disruptive phase, but doesn't contribute much during the flattop region. An effective average responsivity has been estimated for AXUV bolometer for ADITYA.

Copyright (c) 2013 The Japan Society of Plasma Science and Nuclear Fusion Research

Keywords

bolometer, AXUV, radiation, filter, ADITYA, responsivity

DOI: 10.1585/pfr.8.2402124

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References

• [1] K. Tahiliani, R. Jha et al., Plasma Phys. Control. Fusion 51, 085004 (2009).
• [2] S.B. Bhatt et al., Ind. J. Pure Appl. Phys. 27, 710 (1989).
• [3] S.D. Gray et al., Rev. Sci. Instrum. 75, 376 (2004).
• [4] http://www.ird-inc.com/Data/axuv_responsivity.xls
• [5] C.V.S. Rao et al., Rev. Sci. Instrum. 68, 1142 (1997).

This paper may be cited as follows:

Kumudni TAHILIANI, Ratneshwar JHA, Prabhat KUMAR and ADITYA Team, Plasma Fusion Res. 8, 2402124 (2013).