We report a new determination of the Boltzmann constant kB using a cylindrical acoustic gas thermometer. We determined the length of the copper cavity from measurements of its microwave resonance frequencies. This contrasts with our previous work (Zhang et al 2011 Int. J. Thermophys.32 1297, Lin et al 2013 Metrologia50 417, Feng et al 2015 Metrologia52 S343) that determined the length of a different cavity using two-color optical interferometry. In this new study, the half-widths of the acoustic resonances are closer to their theoretical values than in our previous work. Despite significant changes in resonator design and the way in which the cylinder length is determined, the value of kB is substantially unchanged. We combined this result with our four previous results to calculate a global weighted mean of our kB determinations. The calculation follows CODATA's method (Mohr and Taylor 2000 Rev. Mod. Phys. 72 351) for obtaining the weighted mean value of kB that accounts for the correlations among the measured quantities in this work and in our four previous determinations of kB. The weighted mean k̂B is 1.380 6484(28) × 10-23 J K-1 with the relative standard uncertainty of 2.0 × 10-6. The corresponding value of the universal gas constant is 8.314 459(17) J K-1 mol-1 with the relative standard uncertainty of 2.0 × 10-6.

中文翻译：

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用圆柱形声学气体测温法确定玻尔兹曼常数：结合新的和以前的结果

我们报告了使用圆柱形声学气体温度计对 Boltzmann 常数 kB 的新测定。我们通过测量其微波谐振频率来确定铜腔的长度。这与我们之前的工作（Zhang 等人 2011 Int. J. Thermophys.32 1297、Lin 等人 2013 Metrologia50 417、Feng 等人 2015 Metrologia52 S343）形成对比，后者使用双色光学干涉法确定不同腔的长度。在这项新研究中，声学共振的半宽比我们之前的工作更接近于它们的理论值。尽管谐振器设计和确定圆柱体长度的方式发生了重大变化，但 kB 的值基本上没有变化。我们将此结果与我们之前的四个结果相结合，计算出我们 kB 确定的全局加权平均值。计算遵循 CODATA 的方法 (Mohr and Taylor 2000 Rev. Mod. Phys. 72 351)，用于获得 kB 的加权平均值，该平均值解释了本工作和我们之前四次确定的 kB 中测量量之间的相关性。加权平均 k̂B 为 1.380 6484(28) × 10-23 J K-1，相对标准不确定度为 2.0 × 10-6。通用气体常数的对应值为 8.314 459(17) J K-1 mol-1，相对标准不确定度为 2.0 × 10-6。