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Adiabatic Demagnetization Refrigeration (ADR) does not use working fluids contrary to conventional refrigerators that make use of the fluid density difference, which leads to superiority of the ADR under the weak gravity condition. We have been developing a new continuous ADR system to provide the cooling temperatures between 0.06 K and 4 K. The system will consists of multi-stages of magnetic materials and magnets cascaded with heat switches for each temperature range. The ADR cooler is planned to test to confirm the ability of the continuous ADR system under the milli-gravity condition in airborne flight experiments. The ADR development will be accomplished through the collaborative works with NASA/SGFC and JAXA/ISAS., 資料番号: AA0063349055

金沢大学理工研究域数物科学系, Magnetic materials play a significant role in improvement of regenerative cryocooler performance, because they have high volumetric specific heat at magnetic transition temperatures. Gadolinium oxysulfide (Gd2O2S, GOS) that has an antiferromagnetic transition at 5 K improved the cooling performance of cryocoolers when it was used in colder side of the second stage regenerator operating below 10 K. Small magnetic susceptibility and specific heat insensitive to magnetic field is important in order to reduce influence of magnetic field on the performance of cryocooler. We measured magnetization and specific heat of ceramic GOS in magnetic field up to 5 T. The magnetization of GOS represented typical temperature dependence for antiferromagnetic materials and no metamagnetic transition was observed. As for specific heat of GOS, peak temperature decreased from 5.5 to 5.0 K with increasing magnetic field from 0 to 5 T and the transitions remained sharp in magnetic fields. Thermal conductivity of GOS was observed to have very small magnetic field dependence. © Published under licence by IOP Publishing Ltd.

A new continuous Adiabatic Demagnetization Refrigeration (ADR) system has been developed to provide the cooling temperatures between 0.06 K and 4 K. The system will consists of multi-stages of magnetic materials and magnets cascaded with heat switches for each temperature range. The ADR cooler is being tested to confirm the ability of the continuous ADR system under the milli-gravity condition in airborne flight experiments. The ADR development will be accomplished through the collaborative works with NASA/GSFC and JAXA/ISAS., 資料番号: AA0063706032

第26回宇宙利用シンポジウム(2010年1月25日-26日, 宇宙航空研究開発機構宇宙科学研究本部相模原キャンパス), The Twenty-sixth Space Utilization Symposium (January 25-26, 2010: ISAS/JAXA Sagamihara, Japan), Surface waves on superfluid He-4 were optically investigated under 0.5 G, 0.1 G and 0.05 G, using the jet-plane parabolic flight. Assuming that the fundamental mode is excited which is determined by the sample cell width, the resonance peak was well reproduced by the gravity wave with the corresponding gravity constant., 形態: カラー図版あり, 共催: 日本学術会議, Physical characteristics: Original contains color illustrations, joint hosting: The Science Council of Japan, 資料番号: AA0064730007

第25回宇宙利用シンポジウム(2009年1月14日-15日, 宇宙航空研究開発機構宇宙科学研究本部相模原キャンパス), The Twenty-fifth Space Utilization Symposium (January 14-15, 2009: ISAS/JAXA Sagamihara, Japan), Adiabatic Demagnetization Refrigeration (ADR) does not use working fluids contrary to conventional refrigerators that make use of the fluid density difference, which leads to superiority of the ADR under the weak gravity condition. In this study, we developed a continuous ADR system to provide constant cooling temperatures ca. 0.1 K. The system consists of four stages of magnetic materials and magnets cascaded with heat switches. The magnetic materials CPA and GdLiF(sub 4) are used for 3 stages between 0.1 K and 1.4 K, and single stage between 1.4 K and 4 K, respectively. Passive heat switches are used for the stages > 0.3 K and a superconducting heat switch is used for the continuous stage at ca. 0.1 K. A G-M cycle cooler with a 100 V compressor unit is used to cool the ADR and cryostat shieldings. Total mass of flight model is less than 60 kg. Cooling tests with Transition Edge Sensor on the ground showed that the ADR provided continuous cooling temperatures between 105 mK and 120 mK and it successfully operated the TES. Airborne flight experiments confirmed the ability of the cooling system under the mili-gravity condition. The experimental results showed that the ADR could provide stable temperature under the weak gravity, however, strong vibrations coming from turbulence or takeoff affected to the stability of ADR cycle., 形態: カラー図版あり, 資料番号: AA0064297109

第22回宇宙利用シンポジウム(2006年1月17日-19日, 日本学術会議6階会議室 六本木、東京), The Twenty-second Space Utilization Symposium (January 17-19, 2006: Science Council of Japan, Roppongi, Tokyo, Japan), The R&D activities of the working group for space cryocoolers of below-1K-class is introduced. The current target is the ADR development for mu-g physics experiment onboard ISS as well as baseline study for below-1 K-cryocooler for IR and X-ray astrophysical observations., 共催: 日本学術会議, Meeting sponsors: The Science Council of Japan, The Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (ISAS)(JAXA), 資料番号: AA0064113050

第27回宇宙利用シンポジウム (2011年1月24日-25日, 宇宙航空研究開発機構宇宙科学研究所相模原キャンパス), 相模原市, 神奈川県, The Twenty-seventh Space Utilization Symposium (January 24-25, 2011. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS)), Sagamihara, Kanagawa Japan, Adiabatic Demagnetization Refrigeration (ADR) does not use working fluids contrary to conventional refrigerators that make use of the fluid density difference, which leads to superiority of the ADR under the weak gravity condition. We developed a continuous ADR system to provide constant cooling temperatures ca. 0.1 K. The system consists of four stages of magnetic materials and magnets cascaded with heat switches. A G-M cycle cooler with a 100 V compressor unit is used to cool the ADR and cryostat shieldings. Cooling tests with Transition Edge Sensor on the ground showed that the ADR provided continuous cooling temperatures between 105 mK and 120 mK and it successfully operated the TES. The ADR could provide stable temperature under the weak gravity, however, for the experiment of solid helium, the ADR could not achieve below 1K keeping with continuous cycle. This is the reason that the ADR did not have any thermal anchor like 1 K pot. We have been considered a new continuous ADR system which had 5 stages. This ADR will provide two continuous temperatures, 0.1 K and 1-2 K, by using with 3 stages and 2 stages continuous Carnot cycle, respectively., 形態: カラー図版あり, Physical characteristics: Original contains color illustrations, 資料番号: AA0065129008