Experimental techniques: Methods for cooling below 300 mK

Frossati, G.

doi:10.1007/bf00114918

Cited by 43 publications

(10 citation statements)

References 26 publications

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“…The dilution refrigerator followed a PSI design [19] with the substitution of a coiled heat exchanger made of 0.7-mm-innerdiameter × 0.15-mm wall teflon tubing [20]. The refrigerator operation was monitored with RuO resistance thermometers referenced to a calibrated germanium thermometer.…”

Section: Experimental Methodsmentioning

confidence: 99%

Measurement of the relative longitudinal spin-dependent total cross-section difference inn→−d→scattering

et al. 2006

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We report relative measurements of the n− d longitudinal spin-dependent total cross-section difference ( σ L ) d , at E n (lab) = 5.0, 6.88, and 9.0 MeV. The deuteron target was polarized via dynamic nuclear polarization at 250 mK in a 2.5-T external magnetic field. The target polarization was monitored by nuclear magnetic resonance and was calibrated by a ( σ L ) d measurement at E n (lab) = 1.18 MeV. The polarized neutron beams were produced through the 3 H( p, n) 3 He and 2 H( d, n) 3 He reactions. The neutron polarizations were determined either by direct measurement or from known or calculated polarization-transfer coefficients. The results for ( σ L ) d show agreement with theoretical calculations based on nucleon-nucleon potential models but are not of sufficient precision to distinguish the presence or absence of three-nucleon force contributions to the cross sections.

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Section: Experimental Methodsmentioning

confidence: 99%

Measurement of the relative longitudinal spin-dependent total cross-section difference inn→−d→scattering

et al. 2006

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“…The ideal cooling capacity-temperature curve ( ݊ = 1 × 10 ିସ ‫݈݉‬ ‫ݏ‬ ⁄ ) is shown in Figure 5, with complete heat exchange and no heat leakage. Now for a specific dilution refrigerator, assuming that the material of the tube heat exchanger is CuNi alloy (ܴ ெ = 12 × 10 ିଷ ‫ܭ‬ ସ ݉ ଶ ܹ ⁄ ), the following analysis is based on this premise) [13], the influence of 3 He purity on cooling capacity (݊ = 1 × 10 ିସ ‫݈݉‬ ‫ݏ‬ ⁄ and the heat exchange area is 100ܿ݉ ଶ ) is shown in Figure 6. The flow rate increases with the temperature rising.…”

Section: Figure 6 Influence Of 3 He Purity On Cooling Capacitymentioning

confidence: 99%

Thermodynamic Process and Analysis of Dilution Refrigerator

Zheng

Wei

Pan

et al. 2022

IOP Conf. Ser.: Mater. Sci. Eng.

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Thermodynamic analysis is essential for not only guiding the design of refrigerator, but also studying its operation mechanism. As the core component, the dilution unit plays an important role in deciding the performance of dilution refrigerator. In this study, a coupled thermodynamic model is established by analyzing each component separately for improving the operation of dilution refrigerator. And an optimization calculation based on that model is carried out to obtain some meaningful results on the dilution unit design. The optimal flow rate of the dilution refrigerator under different working conditions are pointed out. By considering the effect of viscous heat on the performance of the heat exchanger, the applicable conditions of the continuous heat exchanger and the methods to overcome the viscous heat are given.

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“…CuNi tube-in-tube continuous counterflow heat exchangers have been shown to be well suited to DRs with flow rates on the order of a few μmol/s with 100 mK base temperatures [9]. Several models [9,[18][19][20] estimated the efficiency of the heat exchanger as where the enthalpy coefficients of the diluted and the concentrated phase of the 3 He∕ 4 He mixture are D = 107 J∕K 2 ∕mol and C = 23 J∕K 2 ∕mol [9], respectively, and f is a dimensionless factor given by where A is the surface area of the heat exchanger inner tube, a K is the Kapitza resistivity and T m is the MDR lowest achievable temperature. The area A > 40 cm 2 has been chosen to suit the cooling power requirements, in order to minimize the effect of Kapitza resistance.…”

Section: Designmentioning

confidence: 99%

A Closed-Cycle Miniature Dilution Refrigerator for a Fast-Cooldown 100 mK Detector Wafer Test Cryostat

et al. 2020

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The forthcoming generation of cosmic microwave background polarization observatories is developing large format detector arrays which will operate at 100 mK. Given the volume of detector wafers that will be required, fast-cooldown 100 mK test cryostats are increasingly needed. A miniature dilution refrigerator (MDR) has been developed for this purpose and is reported. The MDR is precooled by a doublestage 3 He-4 He Chase Research Cryogenics sorption refrigerator. The test cryostat based on this MDR will enable fast cooldown to 100 mK to support rapid feedback testing of detector wafers fabricated for the Simons Observatory. The MDR has been designed to provide a 100 mK stage to be retrocompatible with existing CRC10 sorption coolers, reducing the base temperature from 250 mK for the new generation of detectors. Other 250 mK cryostats can be retrofitted in the same way. This configuration will meet the cryogenic requirements for single-wafer testing, providing 5-10 μW of cooling power at 100 mk for over 8 h. The system operates in a closed cycle, thereby avoiding external gas connections and cold o-rings. No moving parts are required, with the system operated entirely by heaters.

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Experimental techniques: Methods for cooling below 300 mK

Cited by 43 publications

References 26 publications

Measurement of the relative longitudinal spin-dependent total cross-section difference inn→−d→scattering

Measurement of the relative longitudinal spin-dependent total cross-section difference inn→−d→scattering

Thermodynamic Process and Analysis of Dilution Refrigerator

A Closed-Cycle Miniature Dilution Refrigerator for a Fast-Cooldown 100 mK Detector Wafer Test Cryostat

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