techniques for approximating the international temperature ... - BIPM

More documents

Recommendations

Info

118 Fig. 12.1: Resistance-temperature characteristic of typical carbon-glass thermometer (solid circles) compared with that of germanium (broken curve) and two Allen- Bradley carbon thermometers (BB: 1/8 W; EG: 1/2 W) [Lawless (1972)]. Although less stable than germanium, carbon-glass thermometers are also less sensitive to a magnetic field, although in magnetic fields higher than 5 to 8 teslas capacitive thermometers are preferable (see Chapter 19).
119 13. Platinum-Cobalt Resistance Thermometers The platinum-cobalt thermometer having a cobalt content of 0.5tomic percent has been developed since 1978 (Shiratori and Mitsui (1978), Shiratori et al. (1982)]. This type of thermometer is available in a standard capsule and in an IPRT-like package (stainless-steel hermetic case). Results of testing and an assessment of stability are available at present only for the industrial type: Shiratori et al. (1982) reported changes of less than 10 mK after several hundreds of cycles between room temperature and 4 K, and Pavese and Cresto (1984) confirmed this behaviour. When the thermometers are cycled between 77 K and 500 K (total heating time ~ 200 h), changes of R(0 °C) are smaller than the equivalent of 100 mK and changes of R(77 K) smaller than the equivalent of 30 mK. Most of the change occurs after the first 50 h of heating. Specific testing for reproducibility between 2 and 20 K [Sakurai and Besley (1985)] has confirmed reproducibility within ± 10 mK when the thermometer is cycled to room temperature, and has shown that it may improve to a few millikelvins if the thermometer need never return above 100 K. Shiratori and Mitsui (1978) studied the resistance/temperature characteristic of the standard type and proposed as a reference function the following equation that fits the experimental points between 3 K and 27 K to within 10 mK: R(T' ) = A R(0 ° C) 0 + A T' + A T' 1 2 3 ( 1+ B T' + B 1 2 T' 2 ) (13.1) where T' = T - 11.732 K; Ao = 7.7510 x 10 -2 ; A1 = 8.6680 x 10 -4 ; A2 = 2.8377 x 10 -6 ; B1 = 2.3167 x 10 -2 ; B2 = 1.4370 x 10 -5 . For the industrial type, the manufacturer supplies a reference table of resistance versus temperature which matches any particular thermometer within ± 0.5 K (4-30 K) or ± 0.4 K (above 30 K). With three calibration points at 0 °C, 77.3 K and 4.2 K, the accuracy is claimed to improve to ± 0.1 K above 16 K and to ± 0.2 K between 4.2 K and 16 K (Shiratori et al. (1982)]. Between 2 K and 29 K a simple sixth-degree polynomial was found to fit the experimental data with a maximum deviation of ± 1 mΩ (equivalent to ± 10 mK) at the sensitivity minimum near 13 K. The estimated accuracy of the experimental data was ± 5 mK (Pavese and Cresto (1984)]. The commercially-available, standard-type platinum-cobalt thermometer is probably less reproducible than the corresponding rhodium-iron thermometer; its stability on thermal cycling is likely to be in the range of a few millikelvins.
Page 1 and 2:
BUREAU INTERNATIONAL DES POIDS ET M
Page 3 and 4:
TECHNIQUES FOR APPROXIMATING THE IN
Page 5 and 6:
iv W(100 °C) = 1.385 (exact value
Page 7 and 8:
Centre for Quantum Metrology Nation
Page 9 and 10:
2. Type J viii a) temperature range
Page 11 and 12:
c) temperature range from 1664.5 °
Page 13 and 14:
xii
Page 15 and 16:
xiv Acknowledgments This monograph
Page 17 and 18:
xvi 3.3.2 Melting Points of Gold (1
Page 19 and 20:
xviii 11.3 Thermal Contact 111 11.4
Page 21 and 22:
1 1. Introduction The Comité Consu
Page 23 and 24:
3 thermometers except in special ex
Page 25 and 26:
5 The accuracies with which tempera
Page 27 and 28:
Table 1.1: Summary of Some Properti
Page 29 and 30:
PART 1: TECHNIQUES AND THERMOMETERS
Page 31 and 32:
11 Fig. 2.1: One form of apparatus
Page 33 and 34:
13 Fig. 2.3: Flow cryostat, shown w
Page 35 and 36:
15 Fig. 2.4: Stirred liquid bath fo
Page 37 and 38:
17 contained within a cylindrical c
Page 39 and 40:
19 Fig. 2.5: Schematic drawing of a
Page 41 and 42:
21 device SRM 767 [Schooley et al.
Page 43 and 44:
23 Table 3.1 : Current Best Estimat
Page 45:
25 The widely-used, but not very re
Page 48 and 49:
28 fraction of sample melted) can g
Page 50 and 51:
30 Fig. 3.2a: Apparatus for the cal
Page 52 and 53:
32 Fig. 3.3: Sealed cell for realiz
Page 54 and 55:
34 Final readings of the thermomete
Page 56 and 57:
36 temperatures differ (usually) sy
Page 58 and 59:
38 Fig. 3.4: Cross sectional drawin
Page 60 and 61:
40 Fig. 3.5: Miniature graphite bla
Page 62 and 63:
42 4. Germanium Resistance Thermome
Page 64 and 65:
44 Fig. 4.3: Example of the Π-type
Page 66 and 67:
46 Fig. 4.4: Differences between dc
Page 68 and 69:
48 - conversely, p-doped thermomete
Page 70 and 71:
50 Fig. 4.6: Effect of a radio-freq
Page 72 and 73:
52 that it will not be subject to m
Page 74 and 75:
ln R n = ∑ i= 0 54 ⎛ ln T - P
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 126 and 127: 106 almost negligible. The final ac
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 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
Page 176 and 177: 156 In the case of the Types K and
Page 178 and 179: 158 temperature is measured with th
Page 180 and 181: 160 19. Thermometry in Magnetic Fie
Page 182 and 183: 162 Type of Sensor T(K) Magnetic Fl
Page 184 and 185: 164 be noted that these lower tempe
Page 186 and 187: 166 Fig. 19.2: The change in calibr
Page 188 and 189:
168 Carbon-glass thermometers (Chap
Page 190 and 191:
Ancsin, J. and Phillips, M.J. (1984
Page 192 and 193:
172 Berry, R.J. (1972): The Influen
Page 194 and 195:
174 Brodskii, A.D. (1968): Simplifi
Page 196 and 197:
176 Crovini, L., Perissi, R., Andre
Page 198 and 199:
Hudson, R.P. (1972): Principles and
Page 200 and 201:
180 Lengerer, B. (1974): Semiconduc
Page 202 and 203:
182 OIML (1985): International Reco
Page 204 and 205:
184 Rusby, R.L. (1975): Resistance
Page 206 and 207:
186 Seifert, P. and Fellmuth, B. (1
Page 208 and 209:
188 Ween, S. (1968): Care and Use o
Page 210 and 211:
190 Fig. A.1: Differences between t
Page 212 and 213:
National Institute of Metrology P.O
Page 214 and 215:
194 Appendix C Some Suppliers of Va
Page 216 and 217:
196 Appendix D Calculations Relativ
Page 218 and 219:
198 4. The calculation of the numbe
Page 220 and 221:
200 Appendix F Interpolation Polyno
Page 222 and 223:
- temperature range from 0 °C to 1
Page 224 and 225:
204 where: d0 = 0; d5 = -3.17578007
show all

techniques for approximating the international temperature ... - BIPM

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?