Performance improvement of a pulse tube cooler below 4 K by use of GdAlO3 regenerator material

Qiu, Limin; Numazawa, Takenori; Thummes, G.

doi:10.1016/s0011-2275(01)00146-1

Cited by 35 publications

(17 citation statements)

References 4 publications

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“…More details of this cooler are given in [3,8,9]. The cooler is driven by a GM-type helium compressor (Leybold CP 6000) with nominal input power of 6 kW.…”

Section: Methodsmentioning

confidence: 99%

“…For operation near 4 K it is impractical to employ normal metals for this purpose since the volumetric specific heat of helium greatly exceeds that of normal metals at liquid helium temperatures. Rare-earth based magnetic intermetallic compounds [4,5] or ceramics [6] with high volumetric specific heat near 4 K have been successfully used as matrix material in the coldest regenerator of 4 K GM-coolers and pulse tube coolers [7][8][9]. In this paper, we propose to employ such magnetic regenerator materials for the damping of temperature oscillations.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Damping of Intrinsic Temperature Oscillations in a 4 K Pulse Tube Cooler by Means of Rare Earth Plates

Allweins¹,

Qiu²,

Thummes³

2008

AIP Conference Proceedings

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“…More details of this cooler are given in [3,8,9]. The cooler is driven by a GM-type helium compressor (Leybold CP 6000) with nominal input power of 6 kW.…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Damping of Intrinsic Temperature Oscillations in a 4 K Pulse Tube Cooler by Means of Rare Earth Plates

Allweins¹,

Qiu²,

Thummes³

2008

AIP Conference Proceedings

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“…The most important requirement for the regenerator materials are large specific heat around the working temperatures. To improve the efficiency, the researchers and engineers are seeking advanced regenerator materials [1][2][3][4] We have reported rare earth nitrides (ErN, HoN, DyN, TbN and GdN) have large specific heat at cryogenic temperatures [5,6]. Among them, ErN shows a peak of specific heat at 4 K. Thus, ErN was expected to be suitable materials for second stage regenerator of 4 K GM cryocoolers.…”

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

Optimization of loading ratio of ErN as regenerator of 4K-GM cryocooler

Nakagawa

Miyauchi

Shiraishi

et al. 2017

J. Phys.: Conf. Ser.

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Abstract. High purity erbium nitride (ErN) spheres with the size range of 150-180 Pm and 180-212 Pm were prepared by nitriding Er metal spheres with low oxygen content. The initial regenerator material of HoCu2 on the cold end of the second regenerator column in 4K-GM cryocooler with nominal cooling power of 0.1 W at 4.2 K was replaced by ErN with different sizes. Higher cooling power was obtained when ErN of smaller size with lower oxygen content was used. We investigated the effect of partial replacement of HoCu2 by ErN in the cold end side of second stage regenerator column on cooling power of 4K-GM cryocoolers. When ErN were substituted for 20 % of HoCu2, the cooling power at 4.2 K reached 0.318 W. This value was 1.36 times as high as that of the cooling power of the GM cryocooler with commercially available regenerator arrangement. Therefore, use of ErN regenerator materials leads to the energy-saving and downsizing of 4K-GM cryocoolers. IntroductionGifford-McMahon (GM) cryocoolers are typical 4 K cryogenic refrigerators widely used for ultra high vacuum pumps, helium and hydrogen liquefaction, and for systems using superconducting magnets such as magnetic resonance imaging diagnosis devices and magnetic levitation trains. However, to obtain 1 W of cooling power at 4.2 K using GM cryocoolers, input power as much as several kW is needed. It is a very important problem to enhance their performances at cryogenic temperatures from the view of the energy saving. The 4K-GM cryocoolers have 2 stages of regenerators. By repeating compress and expansion of helium gas, cryogenic temperate is formed. The first-stage regenerator consists of stacked copper meshes, and the second consists of packed Pb and HoCu2 spheres. The performance and efficiency of the 4K-GM cryocoolers depend on the second stage regenerator materials. The most important requirement for the regenerator materials are large specific heat around the working temperatures. To improve the efficiency, the researchers and engineers are seeking advanced regenerator materials [1][2][3][4].

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“…Usually, these oxides present low Neel temperatures (about 4 K) [3], high melting points (higher than 2400 K) [4], excellent crystal quality [5], and stability under chemical attack [6], making them appropriate and desired to applications as substrates for the epitaxial growth of thin films. Indeed, several works reported the features of thin films grown on, mainly, LaAlO 3 and NdAlO 3 substrates [7,8]. In all cases, there is a role of these substrates in the strain-induced properties.…”

Section: Introductionmentioning

confidence: 99%

Resonance Raman spectroscopy of NdAlO3 single-crystal fibers grown by the laser-heated pedestal growth technique

Marcondes

Rodrigues

Andreeta

et al. 2014

Vibrational Spectroscopy

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Performance improvement of a pulse tube cooler below 4 K by use of GdAlO3 regenerator material

Cited by 35 publications

References 4 publications

Damping of Intrinsic Temperature Oscillations in a 4 K Pulse Tube Cooler by Means of Rare Earth Plates

Damping of Intrinsic Temperature Oscillations in a 4 K Pulse Tube Cooler by Means of Rare Earth Plates

Optimization of loading ratio of ErN as regenerator of 4K-GM cryocooler

Resonance Raman spectroscopy of NdAlO3 single-crystal fibers grown by the laser-heated pedestal growth technique

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