Significant Progress in the Development and Application Validation of 1 K Hybrid Cryocoolers Made by Boreas Cryogenics
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2022-03-27
The team led by Dr. Haizheng Dang proposed a 1 K hybrid refrigeration cycle with a four-stage high-frequency pulse tube cycle as the upper stage and a JT cycle as the terminal. On the basis of 1.52 K achieved in 2021, the temperature was further lowered to 1.36 K, which is the lowest temperature ever publicly reported by a hybrid refrigeration cycle combining multi-stage high-frequency pulse tubes with a JT subsystem. This work was published in CRYOGENICS.
To verify the practical performance of the hybrid cryocooler, the team collaborated with the team of the Shanghai Institute of Microsystem and Information Technology, CAS, to apply the cryocooler to cool the superconducting nanowire single-photon detectors (SNSPDs). Through the measurement of key indicators such as the system detection efficiency (SDE) and dark count rate (DCR). The results indicate that the developed cryocooler can provide effective cooling at 1.84 K and the favourable electrical environment, which ensures the SNSPD to work stably and reliably. The relevant theory and application verification have been published in Chinese Science Bulletin.
With the rapid development of the quantum information technology and deep-space exploration, there is an increasingly urgent demand for cryocoolers operating at temperatures of below 2 K with high reliability, long life, compact, lightweight design, and high cooling efficiency. The multi-stage high-frequency pulse tube coupling JT hybrid cooling cycle represents one of the most critical approaches to achieve this goal. The above research results not only ensure the feasibility of such hybrid cycles for space applications but also accelerate the practical application in broader fields.
Fig. 1. Schematic diagram of the four-stage high-frequency pulse tube coupled with JT hybrid refrigeration system structure and cycle process.
The team has made major progress in the research of pre-cooling multi-stage high-frequency pulse tube cycles. For example, the research on the three-stage high-frequency pulse tube cycle won the CRYOGENICS Best Paper Award 2018. Based on this, the team carryied out the research on the four-stage high-frequency pulse tube cycle, and further proposed a hybrid refrigeration cycle system with four-stage high-frequency pulse tube coupling JT cooler. In 2020, the four-stage pulse tube achieved 3.3 K.
Subsequently, the team conducted in-depth research on the technical approach for achieving sub-2 K with the above-mentioned hybrid cooling cycle. In 2021, a 1.52 K was experimentally obtained. Recently, the record was further refreshed to 1.36 K.
Furthermore, to address the long-standing limitation that most of the existing sub-2 K systems require the use of expensive and rare 3He in the subsystems, which hinders the broader practical adoption, the team proposed a hybrid cooling cycle using relatively cheap 4He as the only working medium. This cycle successfully achieved 1.8 K, verifying the theoretical model and the temperature stability of the superfluid helium medium. This is the first time that a temperature of below 2 K has been experimentally obtained by the hybrid cooling cycle of a four-stage high-frequency pulse tube coupling with a JT system with 4He as the only working medium.
To verify the practical performance of the hybrid cryocooler, the team collaborated with the team of the Shanghai Institute of Microsystem and Information Technology, CAS, to apply the cryocooler to cool the superconducting nanowire single-photon detectors (SNSPDs). Through the measurement of key indicators such as the system detection efficiency (SDE) and dark count rate (DCR). The results indicate that the developed cryocooler can provide effective cooling at 1.84 K and the favourable electrical environment, which ensures the SNSPD to work stably and reliably. The relevant theory and application verification have been published in Chinese Science Bulletin.
With the rapid development of the quantum information technology and deep-space exploration, there is an increasingly urgent demand for cryocoolers operating at temperatures of below 2 K with high reliability, long life, compact, lightweight design, and high cooling efficiency. The multi-stage high-frequency pulse tube coupling JT hybrid cooling cycle represents one of the most critical approaches to achieve this goal. The above research results not only ensure the feasibility of such hybrid cycles for space applications but also accelerate the practical application in broader fields.
Links to the articles:
Experimental validation of a four-stage pulse tube-JT hybrid refrigeration cycle achieving 1.36 K:
A hybrid cryocooler achieving 1.8 K with 4He as the only working medium and its application verification:
Fig. 1. Schematic diagram of the four-stage high-frequency pulse tube coupled with JT hybrid refrigeration system structure and cycle process.
Fig. 2. Typical physical images of the 1.36–1.8 K hybrid cryocooler:
(a) System configuration; (b) Cryogenic stage details.
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