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Influence of the astrophysical requirements on dilution refrigerator design
Cryogenics 39 (1999) 665–669
Influence of the astrophysical requirements on dilution refrigerator design夽 Adriana Sirbi
a,*
, Benjamin Pouilloux
1,b
, Alain Benoit
2,c
, Jean-Michel Lamarre
3,d
a L’AIR LIQUIDE-DTA, BP-15, 38360, Sassenage, France CNES Toulouse, 18, Avenue Edouard Belin, 31401, Toulouse Cedex 4, France c CRTBT, 25, Avenue des Martyrs, 38000 Grenoble, France Institut d’Astrophysique Spatiale, Univiersite´ Paris XI, 91405 Orsay Cedex, France b
d
Received 12 February 1999; received in revised form 12 April 1999; accepted 3 June 1999
Abstract A 300 K to 0.1 K space prototype is developed in cooperation with CRTBT, IAS Air Liquide and RAL, under CNES and ESA contracts, to demonstrate the feasibility of such a cooling system. The heart of the system is a 4 K to 0.1 K open cycle dilution refrigerator circulating 3He and 4He. All the tests are now completed. The design of this system is chosen like the nominal solution for PLANCK/HFI instrument. Since scientific requirements have changed, the design of the prototype has to be adjusted to receive the focal plane of HFI (High Frequency Instrument) instrument of PLANCK. The main goal is to optimise 3He consumption without degrading both mechanical and thermal performances. This paper presents the prototype architecture, the dilution refrigerator and the associated tests. The suitability to PLANCK mission is also assessed. Published by Elsevier Science Ltd. Keywords: Dilution refrigeration; Space cryogenics
1. Introduction One of the most important goals of scientific researches conducted these past years in cosmology is to accurately determine the fundamental cosmological parameters that define our Universe. For that purpose, several projects of observation satellites are in progress in Europe for the search of Cosmic Microwave Background fluctuations. A mission such as PLANCK will require bolometers to be cooled to 0.1 K with a high thermal stability close to a few µK/minute. Systems based on the dilution of 3He into 4He provide such a cooling capability but are limited to ground applications since gravity is used for phase separation. In 1985, Alain Benoit from CRTBT [1–3] developed the 夽 Revised version of a presentation at the “1998 Space Cryogenics Workshop, ESTEC, Noordwijk, NL, July 20–21, 1998”. * Corresponding author. E-mail address: [email protected] (A. Sirbi) 1 [email protected] 2 [email protected] 3 [email protected]
0011-2275/99/$ - see front matter Published by Elsevier Science Ltd. PII: S 0 0 1 1 - 2 2 7 5 ( 9 9 ) 0 0 0 7 6 - 4
open cycle dilution system capable of the same performance without the help of gravity. Such a system is therefore well suited for space applications and it has been decided under an ESA/CNES agreement to build a 0.1 K space dilution demonstrator in order to assess the feasibility of a cooling system from 300 K to 0.1 K. Under the prime contractorship of the Centre National d’Etude Spatiale (CNES) and ESA (European Space Agency), the RAL (Rutherford Appleton Laboratory) is in charge of the mechanical cooler for 20 K and 4 K stages, the CRTBT (Centre de Recherche sur les Tre`s Basses Tempe´ratures) and L’AIR LIQUIDE are in charge of the 4 K/0.1 K cooler, while I.A.S. is the prime contractor of the project. This paper describes the 300 K/0.1 K demonstrator architecture, 4 K/0.1 K open cycle dilution refrigerator with the results of extensive test campaigns conducted in 1997 and 1998. The PLANCK cryogenic system is briefly presented and the suitability of the dilution refrigerator to such a program is also assessed.
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A. Sirbi et al. / Cryogenics 39 (1999) 665–669
2. Dilution refrigerator working principle The open cycle dilution refrigerator is a dilution cooling method with no gravity influence. The type of cooler can be used for space applications; the main advantages are the possibility of working in zero gravity and the absence of moving parts. The cooling process is made using two independent injections: one for pure 3He and one for pure 4He. The gases are pre-cooled, from 300 K to 4 K by an external cooling source. A 1.6 K stage is required to reduce thermal leaks on 0.1 K stage. 3He is dissolved in 4He on the 0.1 K stage. The result is an endothermic process which extracts heat on the 0.1 K stage. Usually the mixture is made under pressure. This pressure is used to pre-cool injected gas at 1.6 K by making a Joule-Thomson expansion on the return line. The mixture has 20% 3He concentration. Only 6.7% is used in the cooling point, so that the dilution process extracts additional power on the return line until the JT expansion. This additional power is used to pre-cool pure 3He and 4He, electrical wires and mechanical supports via a heat exchanger made on input and output lines fixed together and rolled around electrical wires (Fig. 1). The presence of the Joule Thomson expansion requires a low pumping pressure. This can be obtained using a pump on the ground, and the external vacuum in space.
3. Demonstrator architecture A space prototype integrating the open cycle dilution refrigerator is built to prove the feasibility of this cooling process at 0.1 K starting from a 300 K structure. The main objectives were to define under classical spatial constraints (mechanical, thermal, vibrations) a
demonstrator able to cool at a temperature level below 100 mK, a focal plane representative of COBRA/SAMBA payloads (in 1994). The typical scientific requirement is to cool 50 bolometers with 150 electrical wires. The maximum volume specified for the 0.1 K stage was 8 × 8 × 8 cm and an additional mass of 300 grams. The architecture of the prototype consists of: 앫 the open cycle dilution refrigerator used to cool at 0.1 K the detection unit from 4 K, 앫 pre-cooling screens at 20 K, 60 K and 100 K, 앫 the cryo-cooler from RAL used to cool 4 K and 20 K screens. The prototype has three independent circuits for ground tests: 앫 a circuit to pre-cool 100 K, 60 K 20 K and 4 K stages at a temperature level of 20 K. This circuit is used to decrease the cooling time, 앫 a continuous cooling of 60 K and 100 K, 앫 the dilution refrigerator circuit A schematic of this integration is presented in Fig. 2. All frames are in aluminium alloy. Supports between 20 K and 4 K stages are made of CFRP (Carbon Fibre Reinforced Plastic), and 300 K to 20 K supports are made of GFRP (Glass Fibre Reinforced Plastic). The supports between 4–1.6 K and 1.6–0.1 K are made of low thermal conductivity Technorn wires, with, respectively, diameters of 13 mm and 0.9 mm. Wires are fixed with pulleys; three to four revolutions are needed to block the system. Fig. 3 is a photograph of the dilution refrigerator. One can see the 1.6 K stage (Joule-Thomson) suspended on the 4 K stage, and the 150 electrical wires with the dilution circuits wounded around. The 0.1 K stage is not visible. The main characteristics of the dilution prototype are shown in Table 1.
4. Test results on dilution system The mechanical and thermal tests of 4 K/0.1 K dilution prototype have been performed successfully. The mechanical structure passed the qualifications tests with no damage. The tests are made on the three axes for the following signals: 앫 sinus level 20 g 앫 sinus low level 앫 random 0.09 g2/Hz from 80 to 700 Hz Fig. 1.
Schematic of the open cycle dilution system.
The first eigen frequency is 175 Hz.
A. Sirbi et al. / Cryogenics 39 (1999) 665–669
Fig. 2.
667
Schematic of the prototype.
It was noticed that there was a displacement of 0.4 mm of the 0.1 K stage versus 4 K stage due to wires stabilisation in pulleys and/or creeping effect. This can be improved by using other material (Vectran) and gluing wires on the pulleys. Thermal tests were made before and after the vibration tests. The 4 K stage was cooled by liquid helium. The base temperature of 0.1 K was obtained with flow-rates of 2.5 µmol/s for 3He and 10 µmol/s for 4He. The temperature of the 4 K stage has varied between 4.6 K to 5 K. This did not disturb the dilution temperature since the Joule-Thomson stage could support additional heating. The integration of the prototype dilution in the complete demonstrator with the RAL cryo-cooler is the next step. Thermal and mechanical performances will be tested, as well as vibration effects on bolometers. This integration outcome is important for the Planck project.
5. The PLANCK cryogenic system Planck project is a M3 ESA scientific mission. Its objective is the image of the Cosmic Microwaves Background fluctuations and a precise determination of the fundamental cosmological parameters that define our Universe. Two instruments will be mounted on the satellite: the High Frequency Instrument (HFI) and the Low Frequency Instrument (LFI). The bolometers of the HFI instrument require a temperature of 0.1 K with a thermal stability of few µK on 60 seconds. The science time is 1.5 years. The architecture differs from that of the demonstrator.
300 K to 20 K cooling system consists of a passive radiative cooler to achieve 50 K, and a 20 K sorption cooler supplied by the JPL.LFI and HFI are fixed on a common 20 K interface [4]. The dilution refrigerator is used to achieve 0.1 K on HFI, 4 K stage is cooled by a He Joule Thomson system. Descriptions of PLANCK architecture and cryogenic system are given in Figs. 4 and 5. Several changes are required to improve scientific performance. The main evolution in the layout of bolometers equipped with feed horns to control the parasitic light. Update mass on the focal plane is 700 grams. Its diameter is double (⭋ 160 mm). This affects the sample plate which supports bolometers. The total mass of the 0.1 K stage is now about 2 kg, which impacts the mechanical supports and thus the thermal leak on dilution stage. The preliminary mass budget on the three stages is shown in Table 2. A very preliminary design of HFI layout is given in Fig. 6. The effect on PLANCK/HFI definition is discussed hereafter.
6. PLANCK dilution system The increase of mass and volume for PLANCK HFI, can have influence on helium consumption for a dilution system. The objective is to keep the same helium flowrate to reach the working bolometer temperature of 0.1 K, compared with the demonstrator. An optimisation of the heat exchanger between 1.6 K and 0.1 K stages is in progress. This heat exchanger is used to cool electrical wires and supports which are the main contributors in the heat flux balance of 0.1 K stage.
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A. Sirbi et al. / Cryogenics 39 (1999) 665–669
Fig. 4.
Fig. 3.
PLANCK satellite layout.
The dilution system.
Table 1 main characteristics of the dilution prototype Stage
Mass
Dimensions
0.1 K 1.6 K 4K 20 K
0.65 kg 1.1 kg 1.2 kg 1.36 kg
⌽ ⌽ ⌽ ⌽
=8; h =7 cm =17; h =13cm =18; h =18 cm =22; h =25 cm
Cooling power 100 nW 100 µW 2 mW 80 mW
A mathematical model is under construction at CRTBT in order to help to optimise the heat exchanger. Another activity carried out by L’AIR LIQUIDE is the definition of getters to avoid clogging of the dilution circuit and also the definition of clogging detection procedure. Indeed, a delicate point for the dilution circuit is also
Fig. 5.
PLANCK cryogenic system.
the purity of the two gases and particularly the presence of hydrogen. Getters will be fixed along the injection circuit.
A. Sirbi et al. / Cryogenics 39 (1999) 665–669
669
Table 2 preliminary mass budget on the three stages
In particular, each critical point of the instrument shall be tested [5]. We have, in the project, the following tests:
Stage
Mass (kg)
0.1 K 1.6 K 4K
1.9 2 4.2
앫 Thermal stability of bolometers. 앫 Effect of magnetic field (eddy current). 앫 Getters for helium.
8. Conclusions The work which was done for the prototype shows the feasibility of an open cycle dilution circuit, able to cool at 0.1 K 150 electric wires with a 50 nW external heat power. The mechanical supports were designed to support high vibration levels and at the same time to bring very low heat leak on the cold plate which has a mass of 0.5 kg. The good results obtained for the low temperature, flow-rate, mechanical structure give us good support for the design of the cooling system for the Planck satellite. Some delicate points about the purification of gas and the stabilisation of bolometers temperature will be revolved soon. References
Fig. 6.
HFI instrument layout — preliminary.
7. Future of the demonstrator The demonstrator shall be used to help us as much as possible in HFI development, as long as there will not be any mock-up of the instrument.
[1] Benoıˆt A, Pujol S. Dilution refrigerator for space applications with a cryocooler [2] Benoıˆt A, Caussignac M, Pujol S. New types of dilution refrigerator and space applications [3] Benoıˆt A, Pujol S. In: Proceedings of L.T. 19 conference 1989 and A. Benoıˆt, Patent number 8801232 from the Centre National d’Etudes Spatiales, Paris, 1988. [4] The FIRST and Planck “Carrier” missions. Description of the cryogenic systems. Bernard COLLAUDIN, Thomas PASSVOGEL ESA/ESTEC. Proceedings of the 1988 Space Cryogenics Workshop, ESTEC, Noordwijk. The Netherlands, 20–21 July 1998. [5] The susceptibility of Incoherent Detector System to Cryocooler Microphonics. R.S. Bathia (CALTECH) et al. In: Proceedings of the 1988 Space Cryogenics Workshop, ESTEC, Noordwijk. The Netherlands, 20–21 July 1998.
Influence of the astrophysical requirements on dilution refrigerator design夽 Adriana Sirbi
a,*
, Benjamin Pouilloux
1,b
, Alain Benoit
2,c
, Jean-Michel Lamarre
3,d
a L’AIR LIQUIDE-DTA, BP-15, 38360, Sassenage, France CNES Toulouse, 18, Avenue Edouard Belin, 31401, Toulouse Cedex 4, France c CRTBT, 25, Avenue des Martyrs, 38000 Grenoble, France Institut d’Astrophysique Spatiale, Univiersite´ Paris XI, 91405 Orsay Cedex, France b
d
Received 12 February 1999; received in revised form 12 April 1999; accepted 3 June 1999
Abstract A 300 K to 0.1 K space prototype is developed in cooperation with CRTBT, IAS Air Liquide and RAL, under CNES and ESA contracts, to demonstrate the feasibility of such a cooling system. The heart of the system is a 4 K to 0.1 K open cycle dilution refrigerator circulating 3He and 4He. All the tests are now completed. The design of this system is chosen like the nominal solution for PLANCK/HFI instrument. Since scientific requirements have changed, the design of the prototype has to be adjusted to receive the focal plane of HFI (High Frequency Instrument) instrument of PLANCK. The main goal is to optimise 3He consumption without degrading both mechanical and thermal performances. This paper presents the prototype architecture, the dilution refrigerator and the associated tests. The suitability to PLANCK mission is also assessed. Published by Elsevier Science Ltd. Keywords: Dilution refrigeration; Space cryogenics
1. Introduction One of the most important goals of scientific researches conducted these past years in cosmology is to accurately determine the fundamental cosmological parameters that define our Universe. For that purpose, several projects of observation satellites are in progress in Europe for the search of Cosmic Microwave Background fluctuations. A mission such as PLANCK will require bolometers to be cooled to 0.1 K with a high thermal stability close to a few µK/minute. Systems based on the dilution of 3He into 4He provide such a cooling capability but are limited to ground applications since gravity is used for phase separation. In 1985, Alain Benoit from CRTBT [1–3] developed the 夽 Revised version of a presentation at the “1998 Space Cryogenics Workshop, ESTEC, Noordwijk, NL, July 20–21, 1998”. * Corresponding author. E-mail address: [email protected] (A. Sirbi) 1 [email protected] 2 [email protected] 3 [email protected]
0011-2275/99/$ - see front matter Published by Elsevier Science Ltd. PII: S 0 0 1 1 - 2 2 7 5 ( 9 9 ) 0 0 0 7 6 - 4
open cycle dilution system capable of the same performance without the help of gravity. Such a system is therefore well suited for space applications and it has been decided under an ESA/CNES agreement to build a 0.1 K space dilution demonstrator in order to assess the feasibility of a cooling system from 300 K to 0.1 K. Under the prime contractorship of the Centre National d’Etude Spatiale (CNES) and ESA (European Space Agency), the RAL (Rutherford Appleton Laboratory) is in charge of the mechanical cooler for 20 K and 4 K stages, the CRTBT (Centre de Recherche sur les Tre`s Basses Tempe´ratures) and L’AIR LIQUIDE are in charge of the 4 K/0.1 K cooler, while I.A.S. is the prime contractor of the project. This paper describes the 300 K/0.1 K demonstrator architecture, 4 K/0.1 K open cycle dilution refrigerator with the results of extensive test campaigns conducted in 1997 and 1998. The PLANCK cryogenic system is briefly presented and the suitability of the dilution refrigerator to such a program is also assessed.
666
A. Sirbi et al. / Cryogenics 39 (1999) 665–669
2. Dilution refrigerator working principle The open cycle dilution refrigerator is a dilution cooling method with no gravity influence. The type of cooler can be used for space applications; the main advantages are the possibility of working in zero gravity and the absence of moving parts. The cooling process is made using two independent injections: one for pure 3He and one for pure 4He. The gases are pre-cooled, from 300 K to 4 K by an external cooling source. A 1.6 K stage is required to reduce thermal leaks on 0.1 K stage. 3He is dissolved in 4He on the 0.1 K stage. The result is an endothermic process which extracts heat on the 0.1 K stage. Usually the mixture is made under pressure. This pressure is used to pre-cool injected gas at 1.6 K by making a Joule-Thomson expansion on the return line. The mixture has 20% 3He concentration. Only 6.7% is used in the cooling point, so that the dilution process extracts additional power on the return line until the JT expansion. This additional power is used to pre-cool pure 3He and 4He, electrical wires and mechanical supports via a heat exchanger made on input and output lines fixed together and rolled around electrical wires (Fig. 1). The presence of the Joule Thomson expansion requires a low pumping pressure. This can be obtained using a pump on the ground, and the external vacuum in space.
3. Demonstrator architecture A space prototype integrating the open cycle dilution refrigerator is built to prove the feasibility of this cooling process at 0.1 K starting from a 300 K structure. The main objectives were to define under classical spatial constraints (mechanical, thermal, vibrations) a
demonstrator able to cool at a temperature level below 100 mK, a focal plane representative of COBRA/SAMBA payloads (in 1994). The typical scientific requirement is to cool 50 bolometers with 150 electrical wires. The maximum volume specified for the 0.1 K stage was 8 × 8 × 8 cm and an additional mass of 300 grams. The architecture of the prototype consists of: 앫 the open cycle dilution refrigerator used to cool at 0.1 K the detection unit from 4 K, 앫 pre-cooling screens at 20 K, 60 K and 100 K, 앫 the cryo-cooler from RAL used to cool 4 K and 20 K screens. The prototype has three independent circuits for ground tests: 앫 a circuit to pre-cool 100 K, 60 K 20 K and 4 K stages at a temperature level of 20 K. This circuit is used to decrease the cooling time, 앫 a continuous cooling of 60 K and 100 K, 앫 the dilution refrigerator circuit A schematic of this integration is presented in Fig. 2. All frames are in aluminium alloy. Supports between 20 K and 4 K stages are made of CFRP (Carbon Fibre Reinforced Plastic), and 300 K to 20 K supports are made of GFRP (Glass Fibre Reinforced Plastic). The supports between 4–1.6 K and 1.6–0.1 K are made of low thermal conductivity Technorn wires, with, respectively, diameters of 13 mm and 0.9 mm. Wires are fixed with pulleys; three to four revolutions are needed to block the system. Fig. 3 is a photograph of the dilution refrigerator. One can see the 1.6 K stage (Joule-Thomson) suspended on the 4 K stage, and the 150 electrical wires with the dilution circuits wounded around. The 0.1 K stage is not visible. The main characteristics of the dilution prototype are shown in Table 1.
4. Test results on dilution system The mechanical and thermal tests of 4 K/0.1 K dilution prototype have been performed successfully. The mechanical structure passed the qualifications tests with no damage. The tests are made on the three axes for the following signals: 앫 sinus level 20 g 앫 sinus low level 앫 random 0.09 g2/Hz from 80 to 700 Hz Fig. 1.
Schematic of the open cycle dilution system.
The first eigen frequency is 175 Hz.
A. Sirbi et al. / Cryogenics 39 (1999) 665–669
Fig. 2.
667
Schematic of the prototype.
It was noticed that there was a displacement of 0.4 mm of the 0.1 K stage versus 4 K stage due to wires stabilisation in pulleys and/or creeping effect. This can be improved by using other material (Vectran) and gluing wires on the pulleys. Thermal tests were made before and after the vibration tests. The 4 K stage was cooled by liquid helium. The base temperature of 0.1 K was obtained with flow-rates of 2.5 µmol/s for 3He and 10 µmol/s for 4He. The temperature of the 4 K stage has varied between 4.6 K to 5 K. This did not disturb the dilution temperature since the Joule-Thomson stage could support additional heating. The integration of the prototype dilution in the complete demonstrator with the RAL cryo-cooler is the next step. Thermal and mechanical performances will be tested, as well as vibration effects on bolometers. This integration outcome is important for the Planck project.
5. The PLANCK cryogenic system Planck project is a M3 ESA scientific mission. Its objective is the image of the Cosmic Microwaves Background fluctuations and a precise determination of the fundamental cosmological parameters that define our Universe. Two instruments will be mounted on the satellite: the High Frequency Instrument (HFI) and the Low Frequency Instrument (LFI). The bolometers of the HFI instrument require a temperature of 0.1 K with a thermal stability of few µK on 60 seconds. The science time is 1.5 years. The architecture differs from that of the demonstrator.
300 K to 20 K cooling system consists of a passive radiative cooler to achieve 50 K, and a 20 K sorption cooler supplied by the JPL.LFI and HFI are fixed on a common 20 K interface [4]. The dilution refrigerator is used to achieve 0.1 K on HFI, 4 K stage is cooled by a He Joule Thomson system. Descriptions of PLANCK architecture and cryogenic system are given in Figs. 4 and 5. Several changes are required to improve scientific performance. The main evolution in the layout of bolometers equipped with feed horns to control the parasitic light. Update mass on the focal plane is 700 grams. Its diameter is double (⭋ 160 mm). This affects the sample plate which supports bolometers. The total mass of the 0.1 K stage is now about 2 kg, which impacts the mechanical supports and thus the thermal leak on dilution stage. The preliminary mass budget on the three stages is shown in Table 2. A very preliminary design of HFI layout is given in Fig. 6. The effect on PLANCK/HFI definition is discussed hereafter.
6. PLANCK dilution system The increase of mass and volume for PLANCK HFI, can have influence on helium consumption for a dilution system. The objective is to keep the same helium flowrate to reach the working bolometer temperature of 0.1 K, compared with the demonstrator. An optimisation of the heat exchanger between 1.6 K and 0.1 K stages is in progress. This heat exchanger is used to cool electrical wires and supports which are the main contributors in the heat flux balance of 0.1 K stage.
668
A. Sirbi et al. / Cryogenics 39 (1999) 665–669
Fig. 4.
Fig. 3.
PLANCK satellite layout.
The dilution system.
Table 1 main characteristics of the dilution prototype Stage
Mass
Dimensions
0.1 K 1.6 K 4K 20 K
0.65 kg 1.1 kg 1.2 kg 1.36 kg
⌽ ⌽ ⌽ ⌽
=8; h =7 cm =17; h =13cm =18; h =18 cm =22; h =25 cm
Cooling power 100 nW 100 µW 2 mW 80 mW
A mathematical model is under construction at CRTBT in order to help to optimise the heat exchanger. Another activity carried out by L’AIR LIQUIDE is the definition of getters to avoid clogging of the dilution circuit and also the definition of clogging detection procedure. Indeed, a delicate point for the dilution circuit is also
Fig. 5.
PLANCK cryogenic system.
the purity of the two gases and particularly the presence of hydrogen. Getters will be fixed along the injection circuit.
A. Sirbi et al. / Cryogenics 39 (1999) 665–669
669
Table 2 preliminary mass budget on the three stages
In particular, each critical point of the instrument shall be tested [5]. We have, in the project, the following tests:
Stage
Mass (kg)
0.1 K 1.6 K 4K
1.9 2 4.2
앫 Thermal stability of bolometers. 앫 Effect of magnetic field (eddy current). 앫 Getters for helium.
8. Conclusions The work which was done for the prototype shows the feasibility of an open cycle dilution circuit, able to cool at 0.1 K 150 electric wires with a 50 nW external heat power. The mechanical supports were designed to support high vibration levels and at the same time to bring very low heat leak on the cold plate which has a mass of 0.5 kg. The good results obtained for the low temperature, flow-rate, mechanical structure give us good support for the design of the cooling system for the Planck satellite. Some delicate points about the purification of gas and the stabilisation of bolometers temperature will be revolved soon. References
Fig. 6.
HFI instrument layout — preliminary.
7. Future of the demonstrator The demonstrator shall be used to help us as much as possible in HFI development, as long as there will not be any mock-up of the instrument.
[1] Benoıˆt A, Pujol S. Dilution refrigerator for space applications with a cryocooler [2] Benoıˆt A, Caussignac M, Pujol S. New types of dilution refrigerator and space applications [3] Benoıˆt A, Pujol S. In: Proceedings of L.T. 19 conference 1989 and A. Benoıˆt, Patent number 8801232 from the Centre National d’Etudes Spatiales, Paris, 1988. [4] The FIRST and Planck “Carrier” missions. Description of the cryogenic systems. Bernard COLLAUDIN, Thomas PASSVOGEL ESA/ESTEC. Proceedings of the 1988 Space Cryogenics Workshop, ESTEC, Noordwijk. The Netherlands, 20–21 July 1998. [5] The susceptibility of Incoherent Detector System to Cryocooler Microphonics. R.S. Bathia (CALTECH) et al. In: Proceedings of the 1988 Space Cryogenics Workshop, ESTEC, Noordwijk. The Netherlands, 20–21 July 1998.