Abstract In the framework of the ESA X-ray mission ATHENA, scheduled for launch in 2030, an ESA Core Technology Program (CTP) was started in 2016 to build a flight like cryostat demonstrator in parallel with the phase A studies of the ATHENA/X-IFU instrument. As part of this CTP, called the Detector Cooling System (DCS), design, manufacturing and test of a cryostat including existing space coolers will be done. In addition to the validation of thermal performance, a Focal Plan Assembly (FPA) demonstrator using Transition Edge Sensors (TES) detector technology will be also integrated and its performance characterized versus the environment provided by the cryostat. This is a unique opportunity to validate many crucial issues of the cryogenic part of such a sensitive instrument. A dedicated activity within this CTP-DCS is the demonstration of the 300 K-50 mK cooling chain in a Ground System Equipment (GSE) cryostat. The studies are focused on the operation of the space coolers, which is made possible by the use of a ground cooler for cooling cryogenic shields and mechanical supports. This test program is also the opportunity to validate the operation of the cryochain with respect to various requirements, such as time constant and temperature stabilities. This would bring us valuable inputs to integrate the cryochain in DCS cryostat, X-IFU studies, SPICA and LiteBIRD missions. This paper is focused on the operation of the full 300 K – 50 mK cryochain. In particular, the recycling options of the sub Kelvin cooler (sorption cooler + an ADR) versus the capability of 4 K and 2 K JT coolers are described. Results on the JT parameters validation campaign are summarized and eventually the results of the coupled test with sub Kelvin cooler will be presented and discussed.

中文翻译：

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ATHENA X-IFU 300K-50 mK 冷冻链测试结果

摘要 在计划于 2030 年发射的欧空局 X 射线任务 ATHENA 的框架内，欧空局核心技术计划 (CTP) 于 2016 年启动，旨在与 ATHENA/X 的 A 阶段研究并行建造类似低温恒温器的飞行验证器。 -IFU 仪器。作为该 CTP 的一部分，称为探测器冷却系统 (DCS)，将完成包括现有空间冷却器在内的低温恒温器的设计、制造和测试。除了验证热性能外，还将集成使用过渡边缘传感器 (TES) 检测器技术的焦平面组件 (FPA) 演示器，并根据低温恒温器提供的环境表征其性能。这是验证这种敏感仪器低温部分的许多关键问题的独特机会。该 CTP-DCS 中的一项专门活动是在地面系统设备 (GSE) 低温恒温器中演示 300 K-50 mK 冷却链。研究的重点是空间冷却器的运行，这通过使用地面冷却器来冷却低温防护罩和机械支架而成为可能。该测试程序也是验证低温链在各种要求（例如时间常数和温度稳定性）方面的操作的机会。这将为我们在 DCS 低温恒温器、X-IFU 研究、SPICA 和 LiteBIRD 任务中集成冷冻链带来宝贵的投入。本文重点介绍完整的 300 K – 50 mK 低温链的运行。特别地，描述了亚开尔文冷却器（吸附冷却器 + ADR）的回收选项与 4 K 和 2 K JT 冷却器的能力。