Black Radiation Detector*

Eisenman, W. L.; Bates, R. L.; Merriam, J. D.

doi:10.1364/josa.53.000729

Cited by 26 publications

(2 citation statements)

References 4 publications

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“…Finally he also measured the case-heating effect and corrected for it. Stimulated by this work and certain technological advances the decade from 1960 to 1970 saw the start of new programs in absolute radiometry in most of the bigger industrialized countries [7,8,9,10,11,121. However, none of this new work, although of great importance to absolute radiometry in general, suggested the need for additional instrumental corrections or brought about a significant change in the correction philosophy of the instrumental errors.…”

Section: Historical Reviewmentioning

confidence: 95%

An Improved Theory of the Instrumental Corrections for Absolute Radiometers

Hengstberger

1977

Metrologia

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An improved theory of the instrumental corrections applied to absolute radiometers, with the exception of the effect of sensitivity variations across the receiver surface, is derived. After a brief review of the historical emergence of correction factors and finally of a formal correction theory, as formulated by Geist [ 131, some shortcomings of t h s theory are pointed out. Based on a set of strict definitions and the conservation of energy principle a revised theory is derived and a possible experimental procedure for the determination of the various correction factors is described. The new theory also takes into account the influence of deviations from linear response, which to a certain extent are present in all practical absolute radiometers. The ratio of the mean sensitivities for radiant and electrical heating is expressed in terms of either the equivalent or non-equivalent lieat losses. By analyzing the one-dimensional heat flow through a representative model of an absolute radiometer the equivalent and non-equivalent losses are identified. At the same time a formal proof for the conception of the equivalence of the heat loss through the heater wires is provided. All correction terms in the new theory are treated as functions of the applied power and can also be determined as such. In conclusion both the scope and the limitations of the theory are discussed.

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Section: Historical Reviewmentioning

confidence: 95%

An Improved Theory of the Instrumental Corrections for Absolute Radiometers

Hengstberger

1977

Metrologia

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“…By combining equations [6] and [8], we obtain an expression for the relationship c between laser beam absorption and the keyhole dimensions rk and d.:…”

Section: =Q+amentioning

confidence: 99%

Variation of laser energy transfer efficiency with weld pool depth

Fuerschbach¹,

MacCallum²

1995

International Congress on Applications of Lasers &Amp; Electro-Optics

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A series of C 0 2 laser welds were made at a constant beam irradiance of 6 MW/cm2 on 304 stainless steel with travel speeds selected to produce welds with varying levels of weld penetration. Using a Seebeck envelope calorimeter, the net heat input to the part was measured for each weld. It was found that the energy transfer efficiencies varied from 0.29 to 0.86, and decreased at high travel speeds where the weld penetration depth was as shallow as 0.13 mm. The decrease in beam absorption with decreasing weld pool depth is consistent with an absorption mechanism that requires multiple internal reflections within the weld pool. Equations have been developed which connect the keyhole cavity dimensions with the energy transfer efficiency, and correlations with the experimental data have determined the keyhole cavity radius to be 0.1 mm for a focused laser beam with a spot radius of 0.059 mm.

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Ultraviolet sources for photochemical application

Wright

1971

Polymer Engineering & Sci

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Black Radiation Detector*

Cited by 26 publications

References 4 publications

An Improved Theory of the Instrumental Corrections for Absolute Radiometers

An Improved Theory of the Instrumental Corrections for Absolute Radiometers

Variation of laser energy transfer efficiency with weld pool depth

Ultraviolet sources for photochemical application

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