Pulse tube refrigerators are a critical enabling technology for many disciplines that require low temperatures. These refrigerators dominate the total power consumption of most modern cryostats, including those that reach millikelvin temperatures using additional cooling stages. In state-of-the-art commercial pulse tube refrigerators, the acoustic coupling between the driving compressor and the refrigerator is fixed and optimized for operation at base temperature. We show that this optimization is incorrect during the cooldown process, which results in wasted power consumption by the compressor and slow cooldown speed. After developing analytic expressions that demonstrate the need for acoustic tuning as a function of temperature, we dynamically optimize the acoustics of a commercial pulse tube refrigerator and show that the cooldown speed can be increased to 1.7 to 3.5 times the original value. Acoustic power measurements show that loss mechanism(s)—and not the capacity of the compressor—limit the maximum cooling available at high temperatures, suggesting that even faster cooldown speeds can be achieved in the future. This work has implications for the accessibility of cryogenic temperatures and the cadence of research in many disciplines such as quantum computing.

脉冲管制冷机对于许多需要低温的学科来说是一项关键的支持技术。这些冰箱在大多数现代低温恒温器的总功耗中占主导地位，包括那些使用额外冷却阶段达到毫开尔文温度的低温恒温器。在最先进的商用脉冲管制冷机中，驱动压缩机和制冷机之间的声耦合是固定的并针对在基础温度下运行进行了优化。我们发现这种优化在冷却过程中是不正确的，这会导致压缩机浪费电力并降低冷却速度。在开发出证明需要将声学调谐作为温度函数的分析表达式后，我们动态优化了商用脉冲管制冷机的声学效果，并表明冷却速度可以提高到原始值的 1.7 至 3.5 倍。声功率测量表明，损失机制（而不是压缩机的容量）限制了高温下可用的最大冷却，这表明未来可以实现更快的冷却速度。这项工作对低温的可及性以及量子计算等许多学科的研究节奏具有重要意义。