The International Temperature Scale of 1990 (ITS-90) underpins much of modern thermometry, yet efforts to comprehensively characterize and improve its reproducibility have been limited. Here, a low-uncertainty data set drawn from 13 standard platinum resistance thermometers is used to quantify all three main manifestations of scale irreproducibility over the range 13.8033K to 273.16K. Four overlapping ITS-90 subranges are investigated, along with three prospective approaches to temperature scale improvement. The current version of the Guide to the Realization of the ITS-90 is found to overestimate scale realization uncertainties, and recommendations are made to revise the guidance provided therein. Replacing the ITS-90 deviation function of subrange 3 with a new version further improves the interpolation quality of this subrange by a factor of two, and calibrating thermometers at the triple point of xenon rather than the triple point of mercury cuts the realization uncertainty of subrange 4 in half. New linear subranges spanning from the triple point of water to the triple points of mercury or xenon could be added to the scale without compromising the performance of the existing subranges. Combining new interpolation equations with calibration at the triple point of xenon provides the basis for a much more reproducible temperature scale than the ITS-90, with magnification of fixed point uncertainties nearly eliminated for all of subranges 1–4 above the triple point of oxygen.

1990 年国际温标 (ITS-90) 是现代测温学的基础，但全面表征和提高其重现性的努力却很有限。在这里，从 13 个标准铂电阻温度计中提取的低不确定性数据集用于量化 13.8033K 至 273.16K 范围内标度不可再现性的所有三种主要表现形式。研究了四个重叠的 ITS-90 子范围，以及三种改善温标的前瞻性方法。当前版本的 ITS-90 实现指南发现高估了规模实现的不确定性，并建议修改其中提供的指导。用新版本替换子量程3的ITS-90偏差函数，进一步将该子量程的插值质量提高了2倍，在氙气三相点而不是汞三点处校准温度计降低了子量程的实现不确定性4 对半。从水的三相点到汞或氙的三相点的新线性子范围可以添加到标度中，而不会影响现有子范围的性能。将新的插值方程与氙气三相点的校准相结合，为比 ITS-90 更具可重复性的温标提供了基础，