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„ Cryogen-free “ Dilution Refrigerators

50 Years of Dilution Refrigeration , Manchester, 16 September 2015. „ Cryogen-free “ Dilution Refrigerators. Kurt Uhlig Walther Meissner Institute Garching, Germany. 1990: Patrick Pari, Adv Cryog Eng 35: 1079 first cryogen-free DR precooled by GM cryocooler

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„ Cryogen-free “ Dilution Refrigerators

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  1. 50 Years of Dilution Refrigeration, Manchester, 16 September 2015 „Cryogen-free“ Dilution Refrigerators Kurt Uhlig Walther Meissner Institute Garching, Germany

  2. 1990: Patrick Pari, Adv Cryog Eng 35: 1079 first cryogen-free DR precooled by GM cryocooler 1999: delivery of PT4-05 (#2 in CRYOMECH production line) 2002: Cryogenics42: 73 „ 3He/4He DR with pulse tube precooling “ 2007: Prouvé et al., JLTP 148: 909 „Pulse-Tube Dilution Refrigeration Below 10 mK“

  3. „Cryogen-free“ dilution refrigerators Cryomech PT405 T(mc2) = 4.3 mK trap PT1 heatleak: Q(tot) = 70 nW GM-precool: Q(GM) = 170 nW PT2 shield cfhx Cryogenics 44 (2004) 53 IVC flow restriction hx‘s double mc 3He melting curve therm.

  4. „Cryogen-free“ dilution refrigerators • VeriCold Inc.: • noinnervacuumcan (IVC) • bigmixingchamberplate • separate pulse tubesfromrotaryvalve • all electricalfeedthroughs @ 300K • precoolcircuit • (or gas heatswitches, BlueFors) High refrigeration powers (2.5 mW @ 120 mK) (1.75 mW@100 mK) Superconducting magnets (up to 18 T) Clear shots Top loading Bottom loading (cold sample exchange) Automatic cooldown ~ 75% of newly sold DRs are CF

  5. 4He-1K-stage: Q = 100 mW @ 1.3 K (80 m3/h pump) T(min) = 1.05 K CF-DR with 1K-stage (exp. on sc quantum circuits) PT 405 Cryomech PT405 RM: 1st stage: 32 K 40 W@ 75 K 2nd stage: 2.5 K 0.5 W @4 K DR-stage: 0.7 mW @ 100 mK T(min) = 4.0 mK (CMN + fixed point device) CMN sc FPD

  6. Vibrationalheatleak: • runfridge at basetemperature • fill 1K-stage with 4He(liq) • operate 1K-pot in singlecyclemode • turn off pulse tubecryocooler • seeifmixingchambertemperaturedrops • (andmakesure, still temperatureandinletpressureremainunchanged) Cryogenics !

  7. piston cooler cylinder oil 90 mm gear pump ν = 1 Hz el. motor pV - efficiency: η~ 70% J. Hoehne, Cryocoolers 18 (2014) 319 J. Hoehne: arXiv: 1506.08856 (CEC/ICMC 2015)

  8. Thanks for your attention!

  9. „Cryogen-free“ dilution refrigerators Characteristics of dry fridge: Wide geometry, no He, no 1K-pot, automatic cooldown and warmup AUTOMATION! 2004: helium: 5 €/l power 9c / kWh PTR: 25,000 € compare with He-cryostat 20 l (liq) / day ) 2015: helium: 7.50 €/l power 0.201 €/kWh PTR: 33,500 € amortization: 280 days 5kW-PTR (320 days 10 kW-PTR) amortization: 266 days 5kW-PTR (330 days 10kW-PTR)

  10. „Cryogen-free“ dilution refrigerators J. Hoehne: arXiv: 1506.08856 (CEC/ICMC 2015)

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