Closed-Cycle Dilution Refrigerator for LTD in Space Astrophysics

Transcription

1 1 Closed-Cycle Dilution Refrigerator for LTD in Space Astrophysics Philippe Camus 1, G. Vermeulen 1, A. Volpe 1, A.Benoit 1, S. Triqueneaux 1, J. Butterworth 2, S. Martin 2, S. d Escrivan 3,Th. Tirolien 4 1 I.Néel, 2 Air Liquide, 3 CNES, 4 ESA LTD15 (Caltech) June 28, 2013

2 Topics Droplets dilution The OCDR Planck system The CCDR Development Status / pump options Integration examples Conclusions

3 The Droplets dilution A.Benoit & S.Pujol, ILL (2005)

4 The Open Cycle Dilution Refrigerator on Planck o Heat lift : mK o Nominal helium flow rates : - 3 He 6 µmol/s - 4 He 18 µmol/s o Lifetime : 2 years (11000 LNTP 3He)

5 Planck cooler main features o 0.2 W@100mK NET = 20 nk/hz 1/2 o JT 1.6K : 200 W o n 4 = 18 mol/s n 3 = 6 mol/s o 12 tubes NbTi (D = 6 mm, e = 0.2 mm) o 12 thermalization points o Conductive load from 1.6K : 5 W (wires + supports) o Fmod ~ 60Hz (M = 3 kg) a passive clamping system is used during launch S.Triqueneaux et al., Cyrogenics 46 (2006) Planck early results : the thermal performances, A&A 536 (2011)

6 Cooler Integrated within the Instrument HFI

7 Planck specifications mg RMS nW dissipation by viscous damping in FPU suspension ( M = 3kg ) 10-1 specification vibrations on Planck 4K stage 14 g / Hz Hz Suspension mode frequency Kevlar W/O thermalisation Kevlar + thermalisation Mechanical support 1 mg RMS on each JT harmonics 20 mn residual force from JT In-flight dissipation measure ~27nW!

8 N3 (umol/s) Fluid Management PFM TEST PLAN C Worst case maxi +20 C C Worst case mini N4 (umol/s)

9 Improving the system Separation/circulation system: o Still to separate the 3 He and 4 He with a zero gravity liquid dilute mixture confinement o 4 He circulation: fountain pump (T 2.1 K) o 3 He circulation pump (under development) o Cold stage (1.7 K) to reduce the heat load on the still and to condense the 3 He (OCDR has his own 1.6 K stage) (improved) low temperature part of Planck n 4 = 350 mol/s n 3 = 30 mol/s P = 1 50 mk F.Martin et al., Cyrogenics 50 (2010)

10 CCDR Thermodynamics P still = 0.4 / 5 mbar G.Chaudhry et al., Cyrogenics 52 (2012)

11 Cooling power Theoretical cooling power (<300mK) : P = n 4.3.(T 2 -T 02 ) (J/mol.s) G.Chaudhry & G.Vermeulen, JLTP (2012)

12 o Still pressure Performance o Choice ~5-10 mbar o Impact on the pump (classical dilution ~0.1 mbar!) o Requires 1.7K cooling power

13 Phase separator & 4 He pump 3 He 3 He Still box: Still cover fountain pump sponge box Sponge (P160) sponge box orifice capacitive liquid detector Outside still box: still heater still thermometer mixture in D = 50 mm -1g operation A.Volpe Thesis (2013)

14 3He Pump Options Parameter Compression ratio Linear Compressor (JAXA + SHI) 5.4mb / 140mb (@17µmol/s) demonstrated Sorption Compressor (COOLL + U.Twente) 5mb / 200mb (@20µmol/s) expected Holweck Compressor (CNRS + AL) 5mb / 200mb (@20µmol/s) demonstrated 100W@300K (estimated) Input Power (no margin) < 80W 10W@300K (estimated) Mass (without electronics & 20kg 2.2kg 2kg margin) Heat lift below 300K None 80mW@15K None Heritage Based on 1K-Class JT Based on the 4K JT Cooler EM Sorption Cooler EM for compressors Darwin No space heritage except for gas bearings Dev. status BBM under assembly Check valves issue Compression ratio demonstrated Next development steps BBM evaluation 15K demonstrator Demonstrate gas bearings

15 SPICA/BLISS JAXA 1K Class cooling chain 2-stages Stirling 3He JT 6 1.7K K

16 BLISS Instrument (ADR) o 5 bands grating spectrometers ( m) o 4224 low background TES mk o intercept 300 mk (optics) o Cold grating o Cold mass o 50mK o ~25 kg total

17 Support material FOM for maximum stiffness : E(300K)/k(T)

18 Supports thermalization o Heat intercepts 300mK 50mK o F > 150 Hz W/O locking system for launch!

19 Screens C/F rods 300mK stage 50mK / instruments 1.7K stage 4K stage Total mass 25 kg Cold (50mK) 10 kg 1.7K (450X400X400 mm) 50 mk (400X350X350 mm)

20 ATHENA Cooling Chain

21 A CCDR System 2 1 Fluid handling Single mixture storage (20L) 3Helium pump at room temp Fluid lines Counter flow HX Cryogenic filters Fluid connectors for integration Dilution unit Cooling detectors Instrument support Part of the read/out chain ( cables thermalization / cold amplifiers )?

22 Conclusions Closed-Cycle dilution for space is demonstrated in lab (TRL3? But some parts at TRL9+) Performances fully comparable to ADR systems for present needs of large arrays of LTD Advantages : distributed & continuous cooling power No mag shielding needed Next planned step (summer 2014) is a coupled test with a modified JAXA JT1K compressor Looking for an opportunity to build an EBB

23 JAXA JT1K compressor Tests at low massflow Improvement needed on the inlet valve (?) Space qualified, P < 30 W

24 Thermal compressor 24 Need a check valve adaptation for low pressure Acceptable heat load at 15K (100mW) Darwin H2 JT system Design adaptation for the dilution application in progress

25 Drag pump prototype 2 5 www.

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