techniques for approximating the international temperature ... - BIPM
techniques for approximating the international temperature ... - BIPM techniques for approximating the international temperature ... - BIPM
106 almost negligible. The final accuracy achievable with these instruments depends on the overall stability of the various optical components over long periods of time and on the possibility of recalibration at one point using an external lamp or freezing-point blackbody. The long-term stability of these instruments and the preferred calibration techniques for them have still to be assessed.
107 PART 2: TECHNIQUES AND THERMOMETERS TRACEABLE TO THE INTERNATIONAL TEMPERATURE SCALE OF 1990 In all temperature ranges there are thermometers that are widely used because of certain advantages such as low cost and ease of use (e.g. base metal thermocouples), yet they are insufficiently reproducible to be included with those of Part 1. Temperatures measured with them are of course traceable to the ITS-90 through proper calibration procedures. There are also thermometers of only modest quality that are nevertheless extremely useful for certain special measurements (e.g. measurements in the presence of high magnetic fields). In Part 2 there are discussed the more commonly used thermometers in these categories. For the cryogenic range there are included the carbon, carbon-glass, and platinum-0.5% cobalt resistance thermometers, and silicon and gallium arsenide diodes. For higher temperatures, thermistors, liquid-in-glass thermometers, IPRTs, and base-metal thermocouples are so widely used, largely because they can provide in appropriate circumstances adequate reproducibility or accuracy at very low cost, that discussion of them is mandatory. Additionally, Chapter 19 treats the behaviour in magnetic fields of several of the thermometers of both Parts 1 and 2.
- Page 76 and 77: 56 Fig. 5.1: Resistance (Ω) and s
- Page 78 and 79: 58 thermometer wires) caused a more
- Page 80 and 81: 60 6. Vapour Pressure Thermometry*
- Page 82 and 83: 62 transitions, but it could be app
- Page 84 and 85: n ∑ i= 2 64 L x [ Π − k ] P =
- Page 86 and 87: 66 Fig. 6.3: Diagram at constant pr
- Page 88 and 89: 68 Fig. 6.4: Schematic construction
- Page 90 and 91: 70 Fig. 6.6: Use of an evacuated ja
- Page 92 and 93: 72 Following this, the connecting t
- Page 94 and 95: 74 Fig. 6.9: (c) N2, CO, Ar, O2, CH
- Page 96 and 97: 76 the Weber-Schmidt equation [Webe
- Page 98 and 99: 78 Table 6.1: Temperature values (K
- Page 100 and 101: 80 into the bulb (hydrous ferric ox
- Page 102 and 103: 82 Fig. 6.12: Effect on the vapour
- Page 104 and 105: 84 the remaining liquid increases.
- Page 106 and 107: 86 Curie constant (C⊥ is about 0.
- Page 108 and 109: 8.1 General Remarks 88 8. Platinum
- Page 110 and 111: 90 For a group of 45 thermometers h
- Page 112 and 113: 92 More recently, Seifert [(1980),
- Page 114 and 115: 94 For thermometers with W(4.2 K) <
- Page 116 and 117: 96 after 500 h at 1700 °C in air,
- Page 118 and 119: 98 normally extends about 50 cm bac
- Page 120 and 121: 100 inhomogeneities result from the
- Page 122 and 123: 9.5 Approximations to the ITS-90 10
- Page 124 and 125: 104 10. Infrared Radiation Thermome
- Page 128 and 129: 108 11. Carbon Resistance Thermomet
- Page 130 and 131: 110 Fig. 11.1: Resistance-temperatu
- Page 132 and 133: 112 Table 11.1: Typical Time Consta
- Page 134 and 135: 114 calibration after each cool-dow
- Page 136 and 137: 116 12. Carbon-Glass Resistance The
- Page 138 and 139: 118 Fig. 12.1: Resistance-temperatu
- Page 140 and 141: 120 14. Diode Thermometers Diodes c
- Page 142 and 143: 122 2 BT V = E0 − − CT ln ( DT)
- Page 144 and 145: 124 Fig. 15.1: Principal features o
- Page 146 and 147: 126 For a thermometer graduated abo
- Page 148 and 149: 128 rise decreases with time but in
- Page 150 and 151: 130 Fig. 16.1: (a) Fabrication of I
- Page 152 and 153: 132 capillaries of a twin- (or four
- Page 154 and 155: 134 advised to choose the thermomet
- Page 156 and 157: 136 Fig. 16.6: Distribution of the
- Page 158 and 159: 138 and between different thermomet
- Page 160 and 161: 140 therefrom) can then be used wit
- Page 162 and 163: 142
- Page 164 and 165: 144 Fig. 16.8: Tolerances for indus
- Page 166 and 167: 146 Stability on thermal cycling is
- Page 168 and 169: 18.2.1 Type T Thermocouple 148 With
- Page 170 and 171: 150 within ± 0.5 to 0.7 percent. T
- Page 172 and 173: 152 insulation even though it be af
- Page 174 and 175: 154 Table 18.4: Recommended Sheath
106<br />
almost negligible. The final accuracy achievable with <strong>the</strong>se instruments depends on <strong>the</strong><br />
overall stability of <strong>the</strong> various optical components over long periods of time and on <strong>the</strong><br />
possibility of recalibration at one point using an external lamp or freezing-point blackbody.<br />
The long-term stability of <strong>the</strong>se instruments and <strong>the</strong> preferred calibration <strong>techniques</strong> <strong>for</strong> <strong>the</strong>m<br />
have still to be assessed.
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