The axial heat leakage between the cold and hot ends of the regenerator caused by the huge temperature difference is an important part of the cryocooler loss, where the apparent thermal conductivity of regenerator materials is the key parameter that determines the heat leakage. At present, only the apparent thermal conductivity of stainless steel wire mesh, lead and copper sphere above 80 K can be obtained, while measurement results for lower temperatures or other materials are currently not available. A low-temperature apparent thermal conductivity measurement apparatus for regenerator materials has been developed, and the apparent thermal conductivities of sphere-type material (GOS, HoCu₂, Er₃Ni, and lead), mesh-type material (stainless steel wire mesh), and helium-4 under various pressures have been measured. When the regenerator is in a vacuum state (below 10^-4 Pa), the experimental results show that the thermal conduction factors (the ratio of the apparent thermal conductivity of the filled regenerator to that of the material itself) are 0.02 for GOS in 4–10 K temperature range, 0.28 for HoCu₂, 0.43 for Er₃Ni in 4–20 K temperature range, 0.005 for lead sphere and 0.13 for stainless steel wire mesh in 10–40 K temperature range, respectively. However, when the regenerator is filled with helium-4, the thermal conduction factor values increase by one order of magnitude.

由巨大的温差引起的蓄热器冷端和热端之间的轴向热泄漏是低温冷却器损耗的重要部分，其中蓄热器材料的表观导热系数是决定热泄漏的关键参数。目前，只能获得高于80 K的不锈钢丝网，铅和铜球的表观导热率，而目前尚无法获得较低温度或其他材料的测量结果。已经开发出用于再生材料的低温表观热导率测量设备，并且球形材料的表观热导率（GOS，HoCu ₂，Er ₃Ni和铅），网状材料（不锈钢丝网）和氦4在各种压力下的测量。当蓄热器处于真空状态（低于10 ^-4 Pa）时，实验结果表明，对于4中的GOS，导热系数（填充蓄热器的表观导热系数与材料自身的表观导热系数之比）为0.02。在10-20 K的温度范围内，温度范围分别为–10 K，HoCu ₂为0.28 ，Er ₃ Ni为0.43 ，铅球为0.005和不锈钢丝网为0.13。但是，当蓄热室中充满氦4时，导热系数值将增加一个数量级。