Cryogenic Resistance Thermometer Calibrations

1 Page 1 NIST Special Publication 250-91 Calibration of Cryogenic Resistance Thermometers between 0.65 K and 165 K on the International Temperature Scale of 1990 Weston L. Tew This publication is available free of charge from: ht... Open at page → 2 Page 2 NIST Special Publication 250-91 Calibration of Cryogenic Resistance Thermometers between 0.65 K and 165 K on the International Temperature Scale of 1990 Weston L. Tew Sensor Science Division Physical Measurement Laborato... Open at page → 3 Page 3 Certain commercial entities, equipment, or materials may be identified in this document in order to describe an experimental procedure or concept adequately. Such identification is not intended to imply recommendation or... Open at page → 4 Page 4 iii Table of Contents 1.CRYOGENIC RESISTANCE TH ERMOMETRY ................................................................ 1 1.1 Introduction ................................................................................. Open at page → 5 Page 5 iv 6.1 Capsule SPRTs: 13.8 K to 273.16 K................................................................................. 68 6.1.1 SPRT Resistance Measurement Uncertainties .................................................. Open at page → 6 Page 6 v List of Figures 1.1 The normalized resistances of several types of PTC cryogenic resistance thermometers. 1.2 The logarithmic sensitivities of several types of PTC cryogenic resistance thermometers. 1.3 The characteris... Open at page → 7 Page 7 v i 6.5 RIRT resistance measurement uncerta inty components for temperatures over the range 0.65 K to 83.8 K. 6.6 Comparison uncertainties for extended range RIRT calibrations. 6.7 RIRT total calibration uncertainties fo... Open at page → 8 Page 8 v ii List of Tables 2.1 Regular SP-250 Catalog Services for Cryogenic Resistance Thermometer Calibrations performed entirely within the NIST LTCF. 2.2 Regular SP-250 Catalog Services for capsule-type SPRT Calibrations pe... Open at page → 9 Page 9 v iii ABSTRACT Calibrations of cryogenic resistance thermometers at NIST are performed by comparison to standard thermometers on the International Temperature Scale of 1990 (ITS-90). The NIST Low Temperature Calibration... Open at page → 10 Page 10 1 1 Cryogenic Resistance Thermometry 1.1 Introduction The practical measurement of temperatures T below ≈77 K is a highly specialized subject which utilizes a large variety of thermometers depending on the exact applicat... Open at page → 11 Page 11 2 the sign of its temperature-coefficient of resistance (TCR) α(T). The instantaneous TCR is normally defined as: () () dT TdR R T 0 1 ≡ α 1.1 where R is the thermometer resistance at temperature T with a normalization r... Open at page → 12 Page 12 3 values of  S Rare plotted in Figure 1.4 for a sample of thermomete r types discussed in this chapter. 1.0E-04 1.0E-03 1.0E-02 1.0E-01 1.0E+00 0.1 1 10 100 1000 T 90 / K W(T) Figure 1.1 The resistance ratio W(T) chara... Open at page → 13 Page 13 4 1.E-02 1.E-01 1.E+00 1.E+01 0.1 1 10 100 1000 T 90 / K S R Figure 1.2 The logarithmic sensitivities of seve ral types of PTC cryogenic resistance thermometers. See Figure 1.1 for curve identifications. A B C H E F G D Open at page → 14 Page 14 5 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 0.1 1 10 100 1000 T 90 / K R / Ω G-1 G-2 G-3 ZN-1 ZN-2 ZN-3 RO-1 RO-2 RO-3 Figure 1.3. The characteristic Resistance versus Temperature curves for three types each of NTC thermometers... Open at page → 15 Page 15 6 0.1 1.0 10.0 0.1 1 10 100 1000 T 90 / K S G-1 G-2 G-3 ZN-1 ZN-2 ZN-3 RO-1 RO-2 RO-3 Figure 1.4. The absolute magnitude logarithmic sensitivities  S versus temperature curves for three varieties of three NTC thermomet... Open at page → 16 Page 16 7 1.2 Resistance Measurement Four-wire measurements of the thermometer resistance can be performed in either of two modes, a.) constant current I, or b.) constant voltage V excitations. In constant current mode the open-... Open at page → 17 Page 17 8 standard reference resistors. The most accurate systems make the use of current reversals in order to cancel the effects of voltage bias offsets and thermal voltages. Commercial DCC instruments optimized for thermometr... Open at page → 18 Page 18 9 values for η are readily obtained providing the measurement system has adequate resolution. Measurements at two or more currents I 2 > I1 allow a simple calculation using ()() ( ) 21 22 21 d d RI RI T RI IR η − ≅ − 1.4... Open at page → 19 Page 19 10 The third law of thermodynamics requires that all heat transport coefficients such as h= η -1 →0 as T→0. Hence, at low temperatures η exhibits divergent behavior or η ~T −n where typically 0.5 ≤ n ≤ 3 in the temperatu... Open at page → 20 Page 20 11 () () () 2 1 2 2 2 12 2 21 0 II IIRIIR IR − − == . 1.5 Calibrations in terms of R (I=0) are preferable for achieving the highest reproducibility possible for a given thermometer type. By using R (I=0) it is possible t... Open at page → 21 Page 21 12 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 0.1 1 10 100 T / K η mK/mW ZNRT-1030 RIRT-W RIRT-U RIRT-TF RIRT-CE PCRT SPRT MPRT-A MPRT-B RORT GeRT-250AA Figure 1.5. The self-heating coefficient η(T) over the range 0.5 K t... Open at page → 22 Page 22 13 1.4 Thermometer Packaging and Installation Hermetic packaging of the sensor is an important component of cryogenic thermometer design. The details of the packaging technologies are usually proprietary, but the basic f... Open at page → 23 Page 23 14 effects of such contamination would rarely be observable, however, except in cases below ≈40 K where there is no He fill gas present. Installation techniques vary from one application to the next and according to pack... Open at page → 24 Page 24 15 In practice the observed thermal response time is a function of the thermometer mass, the package materials, the package design, and the installation method. Hence, the observed ttr is actually a superposition of seve... Open at page → 25 Page 25 16 time constant of the comparison block can be comparable to ttr (see section 5.3, Figure 5.5) . In this case one is measuring the composite response of the thermometer + comparison block and it is not possible to extra... Open at page → 26 Page 26 17 1.5.1.1 Standard capsule types SPRTs are made from carefully annealed reference grade wire specimens which are mounted in a strain-free fashion and fabricated into capsules sealed with a He fill gas. The wire is norma... Open at page → 27 Page 27 18 eT ≅7 mK·K -1 , a voltage noise of V ne=6 nV or less is necessary. So while it is possible to use SPRTs even below 13.8 K, there are alternative thermometers which are much less demanding on the instrumentation and wh... Open at page → 28 Page 28 19 1.5.1.3 Other types of platinum thermometers The most common type of PRT is the industrial type (‘IPRT’) where the average TCR of 100α= 0.00385 is specified by international standards [48-49]. The standard curve exten... Open at page → 29 Page 29 20 Figure 1.7b A standard capsule SPRT design utilizing a helical coil of Pt wire in a sealed Pt sheath. Figure 1.7c A standard capsule SPRT design utilizing a ‘birdcage’ design for the Pt wire in a sealed Ni-alloy sheat... Open at page → 30 Page 30 21 Figure 1.8 Various commercial designs of capsule type SPRTs, RIRTs, PCRTs, and GeRTs: A. 5.7 OD SPRT with inconel outer sheath [39, 53 ]; B. 5 mm OD SPRT or PCRT with platinum sheath [54] ; C.5.5 mm OD platinum sheath... Open at page → 31 Page 31 22 1.5.2 Rhodium-Iron Rhodium-iron resistance thermometers (RIRTs) are made from a dilute magnetic alloy of 99.5 % Rh and 0.5 % Fe [ 57]. The Rh-Fe system is in a special class of binary alloys exhibiting anomalous posit... Open at page → 32 Page 32 23 with the film flow preserving mass conservation. The onset of this mechan ism of superfluid film flow and evaporation/condensation produces a decrease in η by a factor of 5 to 6. As temperature is lowered still furthe... Open at page → 33 Page 33 24 The stability of CE -RIRTs is very good under thermal cycling and reasonably good under physical handling. Besley [70] has studied the stability of a set of three of these and found stability under 20 thermal cycles b... Open at page → 34 Page 34 25 1.5.3 Platinum- Cobalt Platinum- cobalt resistance thermometers (PCRTs) are another type of dilute magnetic alloy with a low temperature anomaly similar to that of RIRTs [71]. The same 0.5 % atomic concentration is us... Open at page → 35 Page 35 26 PCRTs are calibrated at NIST using the same point spacing and currents as are used for capsule RIRTs. Also like RIRTS, all calibration data are in ohms. The standard ranges are 0.65 K to 24.6 K and 0.65 K to 84 K. Add... Open at page → 36 Page 36 27 GeRT calibrations are normally performed at NIST using bi-polar DC excitation currents I such that the sensor excitation voltage V = IR(T) is in the range 1 mV≤ V ≤ 10 mV. The calibration can be specified to a constan... Open at page → 37 Page 37 28 Figure 1.10 A cross-section of a typical GeRT in a cylindrical hermetic package. (Credit: Blakemore, 1972 [ 76]). 1.5.5 Other NTC Thermometers There are many other semi-conducting NTC thermometers suitable for cryogen... Open at page → 38 Page 38 29 environments. Their sensitivities are l ess than that of GeRTs (see Fig. 1.4) but still more than adequate to achieve 0.1 mK resolution in the liquid- He range. ZNRTs are not interchangeable, but will exhibit a broad... Open at page → 39 Page 39 30 RORTs will exhibit hysteresis effects and abrupt resistance shifts under thermal cycling, presumably due to stress-induced micro- cracks. The cracking process appears to be self-limiting, therefore it is now customary... Open at page → 40 Page 40 31 2 Description of Cryogenic Resistance Thermometer Calibration Services NIST provides regular calibration services for cryogenic resistance thermometers for temperatures ranging between 0.65 K and 83.8 K on the ITS-90.... Open at page → 41 Page 41 32 points. The specific temperatures used by NIST for calibration purposes are given in chapter 5. The calibration uncertainties of these standard service IDs are discussed in chapter 6 . The services listed in table 2.2... Open at page → 42 Page 42 33 Tests which include temperatures in the extended range from 84 K to 165 K may be arranged for within the LTCF for appropriate thermometer types, with higher uncertainties than those achievable for T ≤83.8 K (see chapt... Open at page → 43 Page 43 34 consider this risk. NIST will also tag the thermometer’s lead wire in the event that a manufacturer’s serial number dissolves or otherwise becomes illegible. In the event that a thermometer’s identity becomes in doubt... Open at page → 44 Page 44 35 The calibration information is then entered into the NIST Calibration Support System (CSS) database. Authorized customers may access certain NIST web pages on the CSS through Customer Access portals. This allows the c... Open at page → 45 Page 45 36 3 Overview of the ITS-90 below 273.16 K The ITS-90 is a set of practical definitions for the realization of temperatures which approximate thermodynamic temperature. The scale is defined through fixed poi nt temperatu... Open at page → 46 Page 46 37 Table 3.2. Subranges for the S PRT definitions of the ITS-90 below 273.16 K. Interpolation of temperature on the ITS-90, through the use of SPRTs, is accomplished by three basic steps: a) calibration of the SPRT for a... Open at page → 47 Page 47 38 function’. One reference function spans the range 13.8033 K to 273.16 K (lower range) and the other reference function spans the range 273.15 K to 1234.93 K (upper range). For the purposes of this document, we treat o... Open at page → 48 Page 48 39 3.1.2.1 Calibration Subrange 13.8033 K to 273.16 K (SPRT subrange 1) . The SPRT resistance is measured at the equilibrium hydrogen triple point (e-H2TP), the equilibrium hydrogen vapor pressure point (e-H2VP1) near 33... Open at page → 49 Page 49 40 The coefficients a 3, b3, and c 1 are determined by solving a system of three simultaneous equations using the fixed point calibration data. These data must include the results of the three ratio measurements of W(T O... Open at page → 50 Page 50 41 3.2 ICVGT Definition: 4.2 K to 24.5561 K The ITS-90 defines temperature over the range 3 K to 24.5561 K via an Interpolating Constant Volume Gas Thermometer (ICVGT). The lower limit of the range can be varied dependin... Open at page → 51 Page 51 42 0.1 1 10 100 1000 T 90 / K 3 He VP 4 He VP 4 He VP ICVGT SPRT-1 SPRT-2 SPRT-3 SPRT-4 4 He VPe-H 2TP&VPsNe TPO 2 TPAr TPHg TPH 2O TP Figure 3.1 The structure of the ITS-90 below 273.16 K showing defining sub- ranges. Open at page → 52 Page 52 43 0.001 0.01 0.1 1 10 50 90 130 170 210 250 290 W ( T 90 ) T 90 / K H 2OTP Hg TP Ar TP O 2TP e-H 2 TP e-H 2VP e-H 2NBP Ne TP Figure 3.2 The SPRT reference function for T 90 <5 K. Location of defining fixed points are in... Open at page → 53 Page 53 44 -0.10 -0.08 -0.06 -0.04 -0.02 0.00 0.02 0.04 0.06 0.08 0.10 10 60 110 160 210 260 T 90 T inv -T 90 / mK Figure 3.3 The difference in ITS -90 interpolated temperatures for SPRTs as derived from the inverse function T i... Open at page → 54 Page 54 45 Table 3.5 Coefficients used for the 3 He and 4 He vapor pressure equations (equation 3.11). Range 0.65 K to 3.2 K 1.25 K to 2.1768 K 2.1768 K to 5.0 K Coefficient 3 He 4 He-II 4 He-I a0 1.053447 1.392408 3.146631 a1 0... Open at page → 55 Page 55 46 4 NIST Realizations of the ITS-90: 0.65 K to 273.16 K NIST maintains three separate facilities which are involved in the realization and dissemination of the ITS-90 over the range 13.8 K to 273.16 K [ 104]. Two of the... Open at page → 56 Page 56 47 13.8 K since 1996, but only since 2004 has the ICVGT definition been disseminated in the range 13.8 K to 24.5561 K. Above 24.5561 K, NIST disseminates the ITS-90 via the SPRT sub- range 1 definitions when providing co... Open at page → 57 Page 57 48 Table 4.1 Summary of fixed -point cells currently used at NIST for calibration of as NIST check capsule SPRTs. Fixed Point T90 / K types NIST facilities References e-H2 TP 13.08033 OTPC LTRF [114] STPC LTCF [116], [12... Open at page → 58 Page 58 49 thermometers are long-stem SPRTs, each of which is dedicated for use with a particular fixed point. A complete description is found in reference [ 45]. Starting in 2006, all customer PTC thermometers which go through... Open at page → 59 Page 59 50 Figure 4.4 The adapter probe assembly showing a capsule SPRT installed in an aluminum bushing. 4.2.2 Figure 4.5. The WTP cell maintenance bath with a glass adapter probe installed in a WTP cell. Open at page → 60 Page 60 51 4.2.2 Fixed Points 13.8 K to 83.8 K Prior to 1997, NIST realizations of the ITS-90 cryogenic fixed points (e -H 2 TP, e-H 2 VP1, e-H 2 VP2, Ne TP, O2 TP, Ar TP) were performed by Meyer and Reilly using the LTRF [ 114]... Open at page → 61 Page 61 52 The Ar TP has been realized at NIST since 1978 for capsule SPRTs [110] and since 1971 for long-stem SPRTs [113]. Realizations of the Ar TP were also performed in the LTRF in 1995 - 1996 [ 114]. All NIST check capsule... Open at page → 62 Page 62 53 5 Calibration Procedures Comparison calibrations of customer thermometers at temperatures of 165 K and below are performed in the NIST LTCF. All customer thermometer services for temperatures T <77.35 K are handled ex... Open at page → 63 Page 63 54 RIRTs B-174 and B-168 have been performed also in the LTCF on a regular (approximately annual) basis since 1998. The lower section of Figure 5.1 shows the range of use for the NIST check RIRTs and SPRTs, both within t... Open at page → 64 Page 64 55 0.1 1 10 100 1000 T90 / K Figure 5.1 Temperature ranges for NIST check thermometers and customer calibrations. Lower plot: Ranges of the NIST check RIRTs and check SPRTs as used in the LTCF, and check SPRTs as used in... Open at page → 65 Page 65 56 Table 5.1 Summary of calibration history of NIST capsule check thermometers 1996- 2007. Thermometer Direct Fixed-point Calibrations NIST Comparisons Int’l Comparisons SPRT 1004131 † e-H2 TP, e-H2 VP1, e-H2 VP2, Ne TP,... Open at page → 66 Page 66 57 Figure 5.3 The 3 He cryostat with a large comparison block installed. Figure 5.2 A large comparison block with capsule thermometers installed. address of a scanner switch card for connecting the DUT to the appropriate... Open at page → 67 Page 67 58 0.65 K to 83.8 K. For SPRTs, there are always one to three additional comparison points taken which are intermediate to the fixed-point temperatures. Even though these temperatures are not required for the calibration... Open at page → 68 Page 68 59 such comparisons have not been significantly dependent on which of the two refrigeration modes are used, despite the large difference in heating power levels. The control integration time constants are generally set a... Open at page → 69 Page 69 60 1.0E-03 1.0E-02 1.0E-01 1.0E+00 1.0E+01 1.0E+02 0.1 1 10 100 1000 T/K τ / s τ_inτ τ_exτ τ_inτ + τ_exτ τ_d-Cu Figure 5.5 Estimated time constants for the LTCF comparison block, and estimated thermal response times asso... Open at page → 70 Page 70 61 Table 5.3 The typical set of comparison temperatures, definitions, and measurement currents used for calibrations of cryogenic RTs. Empty cells indicate no data are necessary for that temperature. Currents I1 and I2 (... Open at page → 71 Page 71 62 Figure 5.6 The basic principle of the AC resistance ratio bridge based on an IVD. 5.4 Instrumentation The LTCF normally employs two resistance measurement systems. One is an AC resistance ratio bridge based on a decad... Open at page → 72 Page 72 63 The DC system uses o ne of several stable reference resistors R s (normally1 kΩ, 10 kΩ, and 100 kΩ ) in series with the DUT and a bipolar DC current source. The potential leads are switched between the reference and D... Open at page → 73 Page 73 64 All other cryogenic RTs may be used to interpolate temperature according to whatever equation is found to be both convenient and sufficiently accurate. The interpolation equation is normal ly expressed as resistance a... Open at page → 74 Page 74 65 may not be suitable for numerical interpolation at the same level as the calibration uncertainties. The table’s primary purpose is for the user to check his calculations using the specified fitting function. 5.6 Repor... Open at page → 75 Page 75 66 5.7 Recalibration Intervals and re- normalization NIST has no recommended re-calibration intervals for resistance thermometers. The calibration status of any resistance thermometer depends on its design, construction,... Open at page → 76 Page 76 67 -0.75 -0.50 -0.25 0.00 0.25 0.50 0.75 24 44 64 84 104 124 144 164 Tref / K ∆T / mK 1812279-04B 1774092-04B 1812279-05B 1774095-05B 1774092-05B 1774092-09A 1812282-09A 1812282-06A 1812284-06A U_spchkcomp Figure 5.8. Co... Open at page → 77 Page 77 68 6 Calibration Uncertainties This chapter concerns the ITS-90 calibration uncertainties of capsule SPRTs, RIRTs, and GeRTs at NIST. The specific examples treated here are for: 1.) capsule SPRTs calibrated on the ITS-90... Open at page → 78 Page 78 69 6.1.1 SPRT Resistance M easurement Uncertainties The SPRT resistance measurement uncertainty components actually refer to the uncertainty in the determination of ratio W(T) at each of the required calibration points.... Open at page → 79 Page 79 70 where A(I 1,I2)=(I2 4+I1 4)/(I2 2−I1 2) 2 , B(I 1,I2)=I2 4/(I2 2−I1 2) 2 , ∆Xsh is the self-heating correction in X for I=I 1, and βs is the TCR of the resistance standard. It is assumed that both u( I) and u( X n) ar... Open at page → 80 Page 80 71 terms in Eqn. 6.4 are the uncertainties u Rs(W) associated with the calibration uncertainties u(R s). The next two terms are the uncertainties u TRs(W) associated the thermal stability of the resistance standards. Tab... Open at page → 81 Page 81 72 WTP readings when the same currents are used on the same bridge for both measurements. In this case the self-heating correction uncertainty u sh(W) (the term in the bottom row) in equation 6.5 is modified to account f... Open at page → 82 Page 82 73 6.1.2 SPRT Realization Uncertainties These are mostly type B uncertainty components [125, 126] associated with NIST fixed-point realizations and the resulting ITS-90 interpolation uncertainty over the SPRT subrange 1... Open at page → 83 Page 83 74 samples which are not derived from the atmosphere, but impurity concentrations ≈1 mL/L cannot be ruled out, corresponding to plateau elevations of ≈ 0.012 mK. We assign an uncertainty component u=0.012 mK to reflect a... Open at page → 84 Page 84 75 we assign a standard uncertainty of 0.5 cm. The other factors such as material density, column height, and ∂T/∂P are assigned relative standard uncertainties of 2% or less. 6.1.2.5 Immersion/ Heat Leaks Immersion Cell... Open at page → 85 Page 85 76 isotopic composition used for NIST realizations of the e-H 2 VP points, these ranges are 67 mK and 81 mK for the 101 kPa and 33 kPa VP points, respectively. The standard uncertainties are derived by assuming a rectang... Open at page → 86 Page 86 77 constants and dividing by the wait time of 60 s for 13.8 K<T<54.56 K and 120 s for T ≥54.56 K. The major system time constants are those associated with: 1. ) total self-heating resistance and the internal heat capaci... Open at page → 87 Page 87 78 6.1.4 Check SPRT Calibration Uncertainty The check SPRTs as previously calibrated on the ITS-90 at NIST have calibration uncertainties which are a combination of previous ITS-90 realization uncertainties and SPRT meas... Open at page → 88 Page 88 79 Table 6.4 Cal ibration uncertainties for NIST Check SPRTs as used in the LTCF. Description e-H2 TP† e-H2 VP1† e-H2 VP2† Ne TP† O2 TP† Ar TP† Ar TP‡ Hg TP‡ WTP ‡ Realizations Melting plateau reproducibility 0.064 0.050... Open at page → 89 Page 89 80 -0.2 -0.1 0 0.1 0.2 0.3 10 100 1000 T 90 / K u calchk (T)/mK e-H2TP (j=8) e-H2VP1 (j=7) e-H2VP2 (j=6) NeTP(j=5) O2TP (j=4) ArTP (j=3) HgTP (j=2) H2OTP (j=1) u_calchk (RSS) Figure 6.2 The individual contributions to a... Open at page → 90 Page 90 81 There are two overlapping definitions for the ITS-90 in the interval 13.8 K to 24.556 K which involve two completely different interpolating instruments, the SPRT and the ICVGT. This introduces a second type of non- u... Open at page → 91 Page 91 82 0 0.1 0.2 0.3 0.4 0.5 0.6 10 100 1000 T / K u NU / mK Type 1 Type 2 Type 3 0 0.05 0.1 0.15 0.2 0.25 0.3 10 100 1000 Figure 6.3 The non- uniqueness uncertainties for SPRTs from 13.8 K to 273.16 K. 6.1.6 Total Compariso... Open at page → 92 Page 92 83 which includes only those uncertainty components t hat are of a purely systematic nature. These components are separated from u comp because they occur for both the check SPRT and the batch SPRT so that any associated... Open at page → 93 Page 93 84 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0 20 40 60 80 100 120 140 160 180 T / K u ( T ) / mK u_Comp u_BatM u_ChkCal u_NU-1 u_NU-2 u_NU-3 u_BatCal-Total Figure 6.4 The total calibration standard uncertainty for a batch... Open at page → 94 Page 94 85 6.2 RIRTs 0.65 K to 83.8 K RIRTs are calibrated on the ITS-90 at temperatures as low as 0.65 K. The upper limit is somewhat flexible but NIST offers two standard services with upper limits at 24.556 K and 83.8 K. The... Open at page → 95 Page 95 86 term is the uncertainty u TRs(R)≡u(T RS) associated the thermal stability of the resistance standards. The contributions u Rs do not exceed ≈ 0.022 mK for a 100 Ω RIRT. 6.2.1.2 Parasitic Loading Uncertainties. The par... Open at page → 96 Page 96 87 0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.10 0 10 20 30 40 50 60 70 80 90 T / K u / mK u_INL u_sh u_Rs u_bath u_DNL u_noise u_PL u('R) Figure 6.5 Batch RIRT measurement uncertainty components as a function o... Open at page → 97 Page 97 88 6.2.2.2 ICVGT definition, 5.0 K to 24.556 K These uncertainties have been previously discussed by Meyer and Reilly [103]. In this assessment we have simply allo wed for an error propagation between the ICVGT calibrati... Open at page → 98 Page 98 89 thermal diffusivity time constant of the comparison block td=l 2 /αd , for l=5 cm. The uncertainty estimate is calculated from the time constant ratio multiplied by the magnitude of the self -heating perturbations or... Open at page → 99 Page 99 90 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18 0.20 0 10 20 30 40 50 60 70 80 90 T/K u / mK Check Meas. Ref Stability Thermal Uniformity Thermal Stability (Control) Thermal Equil. Batch Meas A u_Comp Figure 6.6 Com... Open at page → 100 Page 100 91 6.2.5 Non-Uniqueness For the range 0.65 K to 24.556 K, calibrations are accomplished with respect to a NIST check RIRT which has been calibrated at NIST as described in section 5.1. The calibration data are used to pr... Open at page → 101 Page 101 92 uncertainties are a partial RSS of the purely systematic components of the combined measurement uncertainty u cm (see section 6.1.1 and 6.2.1) excluding those quasi -random components already included in u comp (see s... Open at page → 102 Page 102 93 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0 10 20 30 40 50 60 70 80 90 T / K u / mK u_chkcal u_comp u_NU0+u_NU1 u_NU2+u_NU3 u_batcal u_BatCalTotal Figure 6.7 Princip al uncertainty components and total batch RIRT calibration uncert... Open at page → 103 Page 103 94 6.3 GeRT Uncertainties 0.65 K to 24.556 K In this case we are treating the calibration of a device which is in many ways different from the RIRT check thermometers used as references in the comparison process. The com... Open at page → 104 Page 104 95 () (){ } ( ) ()()( )(){ } 2 2 2 2 22 2 cm GeRT s,cal 1 2 s s RS sh GeRT 22 2 2 INL 1 2 DNL n ( ) () , , s u R X u R AI I R u T u R RuX AII uX uX β=++ ++ +  (6.18) It should be noted that in the case of finite curr... Open at page → 105 Page 105 96 calibration. This is a practical compromise which introduces an uncertainty originating from the imperfect reproducibility of the self-heating coefficient η from one installation to another. This is due to the variabl... Open at page → 106 Page 106 97 1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 0.1 1 10 100 T / K u(R) / µΩ/Ω u_Rs,cal u_Ts u_sh u_INL u_DNL u_noise u_cµ 1.E-06 1.E-05 1.E-04 1.E-03 1.E-02 1.E-01 1.E+00 0.1 1 10 100 T / K u(R) / mK u_Rs,cal u_Ts u... Open at page → 107 Page 107 98 6.3.2 ITS-90 Scale-Related Uncertainties The ITS-90-related uncertainties for a GeRT calibration are those which arise in the calibration of the NIST check RIRT and in the various ITS-90 non-uniqueness terms already d... Open at page → 108 Page 108 99 6.3.3.4 RIRT Check Thermometer Measurement In this case, the reference RIRT resistance measurement uncertainty must include all of the individual terms described in section 6.2.1 for the comparison process. Specifical... Open at page → 109 Page 109 100 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0 5 10 15 20 25 T / K u ( T ) / mK u_chkcal u_comp u_NU0 u_NU2 u_batcal-Total Figure 6.9 The principal uncertainty components for the total batch calibration uncertainty in temperature for... Open at page → 110 Page 110 101 6.4.2 NTC Other NTC resistance thermometers such as ZNRTs and RORTs will exhibit calibration uncertainties in temperature similar to those given here for GeRTs. Differences will exist in the resistance measurement un... Open at page → 111 Page 111 102 7 References 1. H. Preston- Thomas, “The International Temperature Scale of 1990 (ITS-90)”, Metrologia 27, 3 (1990); ibid, 107 (1990). 2. L. G. Rubin, Cryogenics , 37 (7), 341- 356 (1997). 3. R. J. Corruccini, “Tempe... Open at page → 112 Page 112 103 26. G. X. Mack, A. C. Anderson, and P. R. Swinehart, Rev. Sci. Instrum , 54, 949- 951 (1983). 27. L. M. Besley and L. Hai, Rev. Sci. Instrum., 64 (3) 748- 755 (1993). 28. S. S. Courts, W. E. Davenport, and D. S. Holm... Open at page → 113 Page 113 104 48. International Electrotechnical Commission, “Platinum Resistance Thermometers and Platinum Sensors” IEC 60751- 2008. 49. American Society for Testing and Materials, “Standard specification for Industrial Platinum... Open at page → 114 Page 114 105 75. J. S. Blakemore, Rev. Sci. Instr . 33, 106- 112 (1962). 76. J. S. Blakemore, in: "Temperature: Its Measurement and Control in Science and Industry", Vol. 4, 827- 833, H. H.. Plumb, ed., Instrument Society of Amer... Open at page → 115 Page 115 106 100. G. F. Strouse, “NIST implementation and realization of ITS-90 over the range 83 K to 1235 K”, in: Temperature: Its Measurement and Control in Science and Industry, Vol. 6, p169, J.F. Schooley, ed., American Inst... Open at page → 116 Page 116 107 115. G.T. Furukawa, “ The triple point of oxygen in sealed transportable cells”, J. Res. Nat. Bur. Stand. (U.S.), 91, 255 (1986). 116. W. L. Tew, “Sealed-cell devices for the realization of the triple point of neon a... Open at page → 117 Page 117 108 132. W. L. Tew and C. W. Meyer, “Adjustment to the NIST Realization of the ITS-90 from 5 K to 24.5561 K”, Report to the CCT, CCT/2008- 09, 2008, Bureau International des Poids et Mesures, Sevres, France. 133. Working... Open at page → 118 Page 118 109 150. F. Pavese, W. L. Tew, and A. G. Steele, in: Proceedings of the 8th International Symposium on Temperature and Thermal Measurements in Industry and Science, TEMPMEKO 2001; Ed. B Fellmuth, (2002). 151. B. W. Mangu... Open at page → 119 Page 119 A-1 Appendix A. Sample Calibration Reports A1 SPRT, 13.8 K to 273.16 K A2 RIRT, 0.65 K to 24.556 K A3 GeRT, 0.65 K to 27.1 K Open at page → 120 Page 120 NIST Service ID No. 33020C Gregory Strouse Test No. 685/123456- 12 Leader, Thermodynamic Metrology Group 12 Apr 2012 Sensor Science Division Purchase Order No. 12345- ABC Page 1 of 2 A1-1 UNITED STATES DEPARTMENT OF COMM... Open at page → 121 Page 121 NIST Service ID No. 33020C Test No. 685/123456- 12 12 Apr 2012 Purchase Order No. 12345- ABC Page 2 of 2 A1-2 Standard Platinum Resistance Thermometer Serial Number 1234567 Submitted by Anybody, Inc. Anywhere, XX USA Coe... Open at page → 122 Page 122 NIST Service ID No. 33140C Gregory Strouse Test No. 685/123456- 12 Leader, Thermodynamic Metrology Group 1 Feb 2012 Sensor Science Division Purchase Order No. 12345- ABC Page 1 of 3 A2-1 UNITED STATES DEPARTMENT OF COMME... Open at page → 123 Page 123 NIST Service ID No. 33140C Test No. 685/123456- 12 1 Feb 2012 Purchase Order No. 12345- ABC Page 2 of 4 A2-2 Rhodium-Iron Resistance Thermometer Serial Number A123 Submitted by ABC Laboratories, Anywhere, USA Table 1. Te... Open at page → 124 Page 124 NIST Service ID No. 33140C Test No. 685/123456- 12 1 Feb 2012 Purchase Order No. 12345- ABC Page 3 of 4 A2-3 A polynomial fit of the resistance as a function of temperature of Rhodium-Iron Resistance Thermometer Serial N... Open at page → 125 Page 125 NIST Service ID No. 33140C Test No. 685/123456- 12 1 Feb 2012 Purchase Order No. 12345- ABC Page 4 of 4 A2-4 Table 3. ITS-90 Interpolation table for the RIRT A-123. Resistance in Ohms. T/K 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0... Open at page → 126 Page 126 NIST Service ID No. 33355S Gregory Strouse Test No. 685/123456- 12 Leader, Thermodynamic Metrology Group 23 Nov 2012 Sensor Science Division Purchase Order No. 123- ABC Page 1 of 5 A3-1 REPORT OF CALIBRATION Internationa... Open at page → 127 Page 127 NIST Service ID No. 33355S Test No. 685/123456- 12 23 Nov 2012 Purchase Order No. 123- ABC Page 2 of 5 A3-2 Germanium Resistance Thermometer Serial Number 12345 Submitted by Anybody, Inc. Anywhere, XX, USA Table 1. As-me... Open at page → 128 Page 128 NIST Service ID No. 33355S Test No. 685/123456- 12 23 Nov 2012 Purchase Order No. 123- ABC Page 3 of 5 A3-3 Germanium Resistance Thermometer Serial Number 12345 Submitted by Anybody, Inc. Anywhere, XX, USA Table 2. Deriv... Open at page → 129 Page 129 NIST Service ID No. 33355S Test No. 685/123456- 12 23 Nov 2012 Purchase Order No. 123- ABC Page 4 of 5 A3-4 Germanium Resistance Thermometer Serial Number 12345 Submitted by Anybody, Inc. Anywhere, XX, USA For the range... Open at page → 130 Page 130 NIST Service ID No. 33355S Test No. 685/123456- 12 23 Nov 2012 Purchase Order No. 123- ABC Page 5 of 5 A3-5 Germanium Resistance Thermometer Serial Number 12345 Submitted by Anybody, Inc. Anywhere, XX, USA Table 4. Inter... Open at page → 131 Page 131 B-1 Appendix B. Glossary of Acronyms ITS-90 International Temperature Scale of 1990 NIST National Institute of Standards and Technology CCT Consultative Committee for Thermometry RT Resistance Thermometer TCR Temperature... Open at page →