Upload
agnes-sullivan
View
214
Download
0
Embed Size (px)
Citation preview
Kurt UhligWalther Meissner Institute
Garching, Germany
50 Years of Dilution Refrigeration50 Years of Dilution Refrigeration, Manchester, 16 September 2015 , Manchester, 16 September 2015
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: Cryogenics 42: 73 „ 3He/4He DR with pulse tube precooling “
2007: Prouvé et al., JLTP 148: 909„Pulse-Tube Dilution Refrigeration Below 10 mK“
heat leak:Q(tot) = 70 nW
GM-precool:Q(GM) = 170 nW
T(mc2) = 4.3 mK
„Cryogen-free“ dilution refrigerators
CryomechPT405
trap
PT1
PT2
IVC
double mc
3He melting curve therm.
Cryogenics 44 (2004) 53
cfhx
flow restriction
hx‘s
shield
„Cryogen-free“ dilution refrigerators
VeriCold Inc.:•no inner vacuum can (IVC)•big mixing chamber plate•separate pulse tubes from rotary valve•all electrical feedthroughs @ 300K•precool circuit•(or gas heat switches, BlueFors)
High refrigeration powers(2.5 mW @ 120 mK)(1.75 mW@100 mK)Superconducting magnets(up to 18 T)Clear shotsTop loadingBottom loading (cold sample exchange)
~ 75% of newly sold DRs are CF
Automatic cooldown
Cryomech PT405 RM:
1st stage: 32 K40 W@ 75 K2nd stage: 2.5 K0.5 W @4 K
4He-1K-stage:
Q = 100 mW @ 1.3 K(80 m3/h pump)T(min) = 1.05 K
DR-stage:
0.7 mW @ 100 mKT(min) = 4.0 mK(CMN + fixed point device)
PT405
CMN sc FPD
CF-DR with 1K-stage(exp. on sc quantum circuits)
Vibrational heat leak:
•run fridge at base temperature•fill 1K-stage with 4He(liq)•operate 1K-pot in single cycle mode•turn off pulse tube cryocooler•see if mixing chamber temperature drops•(and make sure, still temperature and inlet pressure remain unchanged)
Cryogenics !
J. Hoehne: arXiv: 1506.08856 (CEC/ICMC 2015)
J. Hoehne, Cryocoolers 18 (2014) 319
gear pump
el. motor
cylinder
pistoncooler
oil
pV - efficiency: η ~ 70%
90 mmν = 1 Hz
Thanks for your attention!
„Cryogen-free“ dilution refrigerators
Characteristics of dry fridge: Wide geometry, no He, no 1K-pot, automatic cooldown and warmup
2004:helium: 5 €/lpower 9c / kWhPTR: 25,000 €
compare withHe-cryostat20 l (liq) / day )
2015:helium: 7.50 €/lpower 0.201 €/kWhPTR: 33,500 €
amortization: 280 days 5kW-PTR (320 days 10 kW-PTR)
amortization:266 days 5kW-PTR(330 days 10kW-PTR)
AUTOMATION!
„Cryogen-free“ dilution refrigerators
J. Hoehne: arXiv: 1506.08856 (CEC/ICMC 2015)