The sodium D-line is often present in optical spectra of combustion due to its high prevalence and emissivity. Collision theory predicts the spectral peak to have a red-shift dependent on pressure, P, and temperature, T. Here we show that the conditions reached during deflagration of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) permit the red-shift of the sodium D-line to be calibrated to 1.5 GPa. Deflagration at these pressures is achieved using a split Hopkinson pressure bar apparatus, with temperatures of circa 2900 K from the greybody continuum away from spectral features. Lower deflagration pressures, of 0.5 to 0.9 GPa, are achieved in a fallhammer test, with temperatures of circa 4000 K. The red-shift exhibits the predicted PT^−0.7 dependence with a constant of proportionality of (950 ± 30) GPa^-1 · K^0.7 · nm. Using the serendipitous presence of sodium, this optical technique allows for fast measurements of both pressure and temperature from the same light source in one measurement.

由于其高普遍性和发射率，钠 D 线经常出现在燃烧光谱中。碰撞理论预测光谱峰值会发生红移，具体取决于压力P和温度T。在这里，我们表明在 octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) 爆燃期间达到的条件允许将钠 D 线的红移校准为 1.5 GPa。在这些压力下的爆燃是使用分离式霍普金森压力棒装置实现的，灰体连续体的温度约为2900 K，远离光谱特征。在落锤试验中实现了 0.5 至 0.9 GPa 的较低爆燃压力，温度约为4000 K。红移表现出预测的PT ^-0.7依赖性，比例常数为 (950 ± 30) GPa ^-1  · K ^0.7  · nm。利用钠的偶然存在，这种光学技术允许在一次测量中从同一光源快速测量压力和温度。