Close Cycle Dilution for Space

Ph. Camus, G. Vermeulen, G. Chaudhry, A. Benoit, F. Martin

B-POL Workshop, IAP Paris, 29th July 2010

Planck Open Dilution System

Planck System Performances

• Planck system provide 1.6K and 100mK cooling stages from a 4.5K cooler

• Cooling power of 400mW @1.6K and 0.2mW(*) @100mK• Isotopes flow of 18 mmol/s 4He and 6 mmol/s 3He• Needs HP (285 Bar) storage ( 4 X 50L ) for 2 years• Critical pneumatical system for flow control and maintain a

high purity• Full integration of the heat exchanger with the focal plane

and the wires ( thermalization )

(*) + thermalization power of the FP supports and the wires between 1.6K and 0.1K

CCDR Concept

Separation and performances at high 4He flow (F.Martin PhD thesis, 2009)

BLISS Study

• Mass Budget– Cold H/W (including IOB)< 150 kg

• 50 kg for SAFARI

• Thermal Budget– 15 mW @ 4.5 K (FPI Total)– 5mW @1.7K (FPI Total)

• Volume• FPI Position• Warm Electronics

Double stage ADR solutionGrating Spectrometers + screens > 9kg at 50 mK !0.4 mW at 50mK

Carbon fiber supports

Advantage to C/F rods

4K stage

1.7K stage

300mK stage

50mK / instruments

C/F rods

Screens

Heat intercept between 300-50mK

200 mmol/s 4He30 mmol/s 3He

W/O locking system for launch !

System aspectsCryo device integrated functions :- Cooling detectors- Instrument support- Part of the read/out chain (cables

thermalization / cold amplifiers ) ?

3Helium circulation (30 mmol/s - 5/200 mBar)• Cold pump• Room temp pump

• Isotopes storage• Integration (Planck-like)

Solutions for 3He pump

• Space qualified mechanical pumps– JAXA JT3HE compressor adaptation– Thales PT compressor adaptation– High speed drag pump

• Cryo pump– Twente development for Darwin

=> The two options will kept

High speed drag pumpCreare technology (space qualified)Technical proposal under discussion200000 RPMGas bearing

Adixen commercial productCEA/AirLiquide design study60000-120000 RPMMag bearings

Cryogenic pump

•Darwin H2 JT system•Design adaptation for the dilution•Need a check valve adaptation for low pressure•Acceptable heat load at 15K/50K (100mW)

Conclusions

• Cooling performances achieved 1mW @ 50mK (TRL3-4)

• Re-use of the BLISS case for B-POL• Need to have a complete engineering model– 0 G still demonstration– Pump choice / development (prob. Two solutions)

• Supported by Cnes (PhD A. Volpe) and ESA (ITI)• Objective TRL4 in June 2011