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Bolometer

75 R-1

On DIII-D two bolometer arrays provide measurements of the radiated power distribution and the total radiated power. Both arrays consist of 24 channels and span the entire plasma. The arrays are located at 45 R-1 and 60 R+1. The detectors are temperature sensors which rise in temperature due to incident plasma radiation. The raw signal is digitizer voltage which is proportional to the change in detector temperature. The power incident on each detector is calculated from the raw signal based on the thermal characteristics of that detector. The averaging time for the power signals is currently 40msec. The individual power signals are combined into global radiation signals based on geometry assumptions of the radiation distribution for standard discharges. These assumptions lead to an uncertainty of ~20% in total radiation. An inversion of the data into a 2D profile is necessary for a more accurate determination. The timetrace signals can be viewed using REVIEW or the 4D idl code using the pointnames given below. For inverting the raw signals into 2D radiation profiles the 4D code is used. The radiated power module in profile analysis section can invert the signals for a given timeslice into a 2D radiation profile. An efit is required for each desired timeslice.