Experimental determination of the absolute temperature modulation in photothermal microscopy of Y1Ba2Cu3O7 crystals

We have obtained the transition probabilities of the 5577 Å, and 6300 Å lines of [OI] by simultaneously measuring the absolute intensity and the population of the upper state of each line in an inert gas–oxygen discharge. Further, we have obtained A values for the 2972 Å and 6364 Å lines by measuring relative intensities of lines from the 1S0 and 1D2 levels.

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A determination of the radiation constant

Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character ◽

10.1098/rspa.1913.0005 ◽

1913 ◽

Vol 88 (600) ◽

pp. 49-60 ◽

Cited By ~ 8

Keyword(s):

Absolute Temperature ◽

Absolute Zero ◽

Fourth Power ◽

Net Radiation ◽

A Value ◽

The Absolute ◽

Boltzmann Law

According to the Stefan-Boltzmann law, the radiation emitted by a full radiator is surroundings at a temperature of absolute zero is proportional to the fourth power of the absolute temperature of the radiator, or R = σθ 4 , where R = radiation in ergs per cm 2 . per sec., θ = absolute temperature of radiator, σ = radiation constant. If the radiator is in surroundings at absolute temperature θ 1 , which are themselves full radiators, then R´ = R θ -R θ 1 = σ( θ 4 - θ 1 4 ), where R´ is the net radiation. The first important determination of the radiation constant is due to Kurlbaum, who obtained a value 5·33 × 10 -5 erg/sec. cm. 2 deg. 4 , recently corrected to 5·45 × 10 -5 erg/sec. cm. 2 deg. 4 Later investigations give results varying considerably from Kurlbaum's and from one another, and, on the whole, they indicate that Kurlbaum's value is too low. Some determinations are given in the following table:—

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A new method of determining the radiation constant

Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character ◽

10.1098/rspa.1912.0012 ◽

1912 ◽

Vol 86 (585) ◽

pp. 180-196 ◽

Cited By ~ 8

Keyword(s):

Black Body ◽

Absolute Temperature ◽

Absolute Zero ◽

New Method ◽

Platinum Black ◽

Main Current ◽

First Case ◽

Black Surface ◽

The Absolute

According to stefan's law the rate of radiation of energy from a full radiator in surroundings at a temperature of absolute zero is σ θ 4 ergs per cm. 2 per sec., where θ is the absolute temperature of the radiator. If the radiator be in surroundings which are themselves full radiators, but at absolute temperature θ 1 , the rate of loss of energy by radiation is taken to be σ( θ 4 - θ 1 4 ). The classical determination of the constant σ is due to Kurlbaum, who used a surface bolometer with a platinum-black surface. The rise of temperature of the bolometer when exposed to the radiation from an approximately full radiator or "black body" was observed. The radiation was then cut off, and an equal rise of temperature was produced by increasing the main current in the bolometer. It was assumed that the energy received per second from the radiator in the first case was equal to the energy received per second from the increase of current in the second ease. The resulting value of σ was 5·33 x 10 -5 ergs per cm. 2 per sec. per deg. 4 , or 5·33 x 10 -12 watts per cm. 2 per deg. 4 .

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