Abstract We describe the design and in–flight performance of the cryostat and the self–contained 3 He refrigerator for the OLIMPO balloon–borne experiment, a spectrophotometer to measure the Sunyaev–Zel’dovich effect in clusters of galaxies. The 3 He refrigerator provides the 0.3 K operation temperature for the four arrays of kinetic inductance detectors working in 4 bands centered at 150, 250, 350 and 460 GHz. The cryostat provides the 1.65 K base temperature for the 3 He refrigerator, and cools down the reimaging optics and the filters chain at about 2 K. The integrated system was designed for a hold time of about 15 days, to achieve the sensitivity required by the planned OLIMPO observations, and successfully operated during the first long–duration stratospheric flight of OLIMPO in July 2018. The cryostat features two tanks, one for liquid nitrogen and the other one for liquid helium. The long hold time has been achieved by means of custom stiff G10 fiberglass tubes support, which ensures low thermal conductivity and remarkable structural stiffness; multi–layer superinsulation, and a vapour cooled shield, all reducing the heat load on the liquid helium tank. The system was tested in the lab, with more than 15 days of unmanned operations, and then in the long duration balloon flight in the stratosphere. In both cases, the detector temperature was below 300 mK, with thermal stability better than ± 0.5 mK. The system also operated successfully in the long duration stratospheric balloon flight.

中文翻译：

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OLIMPO 气球携带实验的长持续时间低温系统：设计和飞行性能

摘要 我们描述了低温恒温器的设计和飞行性能，以及用于 OLIMPO 气球携带实验的独立 3 He 冰箱，这是一种用于测量星系团中 Sunyaev-Zel'dovich 效应的分光光度计。3 He 制冷机为四个动态电感探测器阵列提供 0.3 K 的工作温度，这些探测器在以 150、250、350 和 460 GHz 为中心的 4 个频段中工作。低温恒温器为 3 He 冰箱提供 1.65 K 的基础温度，并将重新成像光学器件和过滤器链冷却到大约 2 K。集成系统设计为大约 15 天的保持时间，以达到所需的灵敏度计划的 OLIMPO 观测，并在 2018 年 7 月 OLIMPO 的第一次长时间平流层飞行中成功运行。低温恒温器有两个罐，一种用于液氮，另一种用于液氦。通过定制的刚性 G10 玻璃纤维管支撑实现了较长的保持时间，确保了低导热性和卓越的结构刚度；多层超绝缘层和蒸汽冷却罩，所有这些都减少了液氦罐的热负荷。该系统在实验室进行了超过 15 天的无人操作测试，然后在平流层进行了长时间的气球飞行。在这两种情况下，检测器温度均低于 300 mK，热稳定性优于 ± 0.5 mK。该系统还在长时间的平流层气球飞行中成功运行。确保低导热性和卓越的结构刚度；多层超绝缘层和蒸汽冷却罩，所有这些都减少了液氦罐的热负荷。该系统在实验室进行了超过 15 天的无人操作测试，然后在平流层进行了长时间的气球飞行。在这两种情况下，检测器温度均低于 300 mK，热稳定性优于 ± 0.5 mK。该系统还在长时间的平流层气球飞行中成功运行。确保低导热性和卓越的结构刚度；多层超绝缘层和蒸汽冷却罩，所有这些都减少了液氦罐的热负荷。该系统在实验室进行了超过 15 天的无人操作测试，然后在平流层进行了长时间的气球飞行。在这两种情况下，检测器温度均低于 300 mK，热稳定性优于 ± 0.5 mK。该系统还在长时间的平流层气球飞行中成功运行。检测器温度低于300 mK，热稳定性优于±0.5 mK。该系统还在长时间的平流层气球飞行中成功运行。检测器温度低于300 mK，热稳定性优于±0.5 mK。该系统还在长时间的平流层气球飞行中成功运行。