Cooling performance of Joule Thomson coolers in 300

Cooling performance of Joule Thomson coolers in 300 K – 50 m. K cryochain demonstration for ATHENA X-IFU K. Shinozaki 1), C. Tokoku 2), R. Yamamoto 2)*, Y. Minami 3), N. Y. Yamasaki 2), K. Mitsuda 2), T. Nakagawa 2), J. M. Duval 4), T. Prouvé 4), I. Charles 4), M. Le Du 5), J. André 5), C. Daniel 5), M. Linder 6), S. Tsunematsu 7), K. Kanao 7), K. Otsuka 7) and K. Narasaki 7) 1) JAXA / R&D, Japan 2) JAXA / ISAS, Japan 3) High Energy Accelerator Research Organization (KEK), Japan 4) Univ. Grenoble Alpes, CEA, INAC, SBT, France 5) CNES Toulouse, France 6) ESA-ESTEC, Netherlands 7) Sumitomo Heavy Industries, Lt. D. , Japan * AIST, Japan at present 27 th International Cryogenic Engineering Conference, 3 -7 th September 2018, Oxford, UK 1

Introduction u 50～ 100 m. K Cooling system for space science missions l Athena : 2 nd L-class X-ray astronomical mission by ESA cosmic vision l SPICA : Space infrared telescope for cosmology and astrophysics by ESA / JAXA l Lite. BIRD: CMB B-mode polarization detection satellite by JAXA u Detector cooling system (ESA Core Technology Program = CTP) l Design and develop a detector cooling system (DCS). l Validation of cryogenics operation. l Integration and test of a functional FPA (from SRON). l Assess perturbation induced by microvibration and EMC. u Intermediate step: 300 K – 50 m. K cryochain operation (Cryostat 1) l Dedicated cryostat in France (CEA Grenoble). l Coupling of international coolers. • 50 m. K cooler, Joule Thomson coolers, etc. . l Validation of cryocoolers operation. l Additional cryocoolers characterizations. l 300 K – 50 m. K operation validated. Lite. BIRD 2

1. Cooler system developments u CTP Cryostat 1: Common I/Fs in several mission’s cooler systems can be tested. CTP (Athena X-IFU) 50 m. K cooler SPICA Lite. BIRD 300 m. K Sorption cooler + ADR (CNES/CEA) 2 K cooler 2 K-JT (JAXA/SHI or RAL) 4 K cooler 2 K-JT (JAXA/SHI) 4 K-JT (JAXA) Pre-cooler Note PT 15 K (ESA/CEA/AL/TAS) 2 ST (JAXA/SHI) Vacuum dewar Radiative cooling Same thermal I/F 2 K-JT : 1 K-class Joule Thomson cooler 4 K-JT : 4 K-class Joule Thomson cooler 2 ST : Double-stage Stirling cooler PT 15 K: 15 K-class Pulse Tube cooler ESA RAL CEA AL TAS : European Space Agency : Rutherford Appleton Lab. (UK) : Commissariat a L’energie (FR) : Air Liquide Co. : Thales Alenia Space Co. u ２ ST, 4 K-JT and 2 K-JT have been developed by JAXA. 2 K-JT 50 m. K cooler (CEA) 2 K-JT Common I/Fs Fig. SPICA cooler system K. Shinozaki et al. SPIE (2016) 3

2. Cryostat 1 design u CTP Cryostat 1: Cooler system demonstration including trade-off study. l The cubic vacuum vessel is used. Easy integration, open and close. l 4 K commercial cooler is used to cool outer (~100 K) and inner (5~30 K) shield. l PT 15 K developed by ESA/CEA/AL/TAS has been coupled with 2 K-JT as a pre-cooler. PT 15 K (CEA) 2 K-JT (JAXA) 50 m. K hybrid cooler (CEA) 4 K-JT (JAXA) T. Prouvé et al. Cryogenics (2018) 2 ST (JAXA) 4

3. Mechanical coolers in JAXA / SHI Double stage stirling cooler (2 ST) 4 K-class Joule Thomson cooler (4 K-JT) SHI: Sumitomo Heavy Industry 1 K-class Joule Thomson cooler (2 K-JT) Compressors (x 4) ↓ 　　　→ 　↑ Cold Head Compressor Cold Part → Compressors (x 2) ↑ Cold → Part TRL 8 TRL 5 (life time test is ongoing) Specification: Operating temp: -70~+30 deg. C Operating temp: 0~+30 deg. C Input power: 80 W at EOL Input power: 90 W at EOL Input power: 75 W at EOL Mass: 9. 5 kg Mass: 15 kg Mass: 28 kg Driving freq. : 15 Hz Driving freq. : 52 Hz Driving freq. : 40 Hz (L 1, L 2), 52 Hz (M, H) Mission: Cooling power: >200 m. W at 20 K and >1 W at 100 K (EOL) Life time: >3 years (5 yrs as a goal) Akari (2006) JEM / SMILES (2009) Astro-H / SXS (2015) SPICA (late 2020 s) Athena (late 2020 s) Lite. BIRD (mid 2020 s) Cooling power: 40 m. W at 4. 5 K (EOL) Life time: > 3 yrs (5 yrs as a goal) JEM/SMILES (2009) Astro-H/SXS (2015) SPICA (late 2020 s) Athena (late 2020 s) Lite. BIRD (mid 2020 s) Cooling power: 10 m. W at 1. 7 K (EOL) Life time: >5 yrs SPICA (late 2020 s) Athena (late 2020 s) Lite. BIRD (late 2020 s) 5

4. JT coolers test sequence and test items (1/2) u 4 K-JT with 2 ST precooler l A vacuum vessel was used for the pre / post-shipment cooling test as well as the transport from Niihama Japan to CEA France. l The verification of the cooling performance between before and after the transport. The different condition between the vacuum vessel and the cryostat 1 is also considered. u 2 K-JT (PT 15 K as a precooler, transported with PT 15 K dummy) l No cooling verification was performed before the transport, since 1) diameter and total length of the heat exchanger were only updated to fit the PT 15 K, 2) 30~50% margin was considered in the heat exchange length design, 3) the design can be verified by gas flow rate, pressure and temperature distribution. l 2 K-JT compressors performance has been verified before and after the transport. u Unit performance of each JT cooler and GSE cooler have been measured. Feb~Mar 2017 GSE cooler installation in to cryostat 1 and cooling test Feb~Mar 2017 4 K-JT unit cooling test in vacuum vessel (pre / post shipment) May 2017 Green: CNES/CEA (in Grenoble) Blue: JAXA/SHI Integration of 2 K-JT with PT 15 K Apr 2017 4 K-JT installation into cryostat 1 and cooling test Mar~Jul 2017 2 K-JT installation and cooling test (4 He, 3 He) Sep~Oct 2017, Feb 2018 50 m. K cooler Installation and cooling test 6

4. JT coolers test sequence and test items (2/2) u Operation methods and the JT temperature behavior during the sub-K cooler recycle. l There are mainly 3 kinds of operation methods by taking into account the relation between driving power, temperature and cooling power. l Passive operation (constant driving power) or active operation (active heater, or active variation of driving power) should be determined by the cooling test. u The heat load of each JT at each steady state (Observation mode, stand-by mode) l These heat load and interface requirements determine the driving power. Sorption pump temperature Specific cooling power 20 4 K-JT coldtip temperature 4. 7 Tβ K 4. 5 Tα K Total Heat load 4. 3 Heat load into 4 K-JT Total 40 α 20 From Hyb. C 0 0 m. W 0 5 Time (hour) α m. W 0 m. W 10 40 Tα K Stand-by mode Pis col ton lisi on T (K) 0 Cooling power (m. W) T (K) 40 20 0 4. 3 Tβ K The 50 m. K cooler recycling mode Dryou t Constant input power (Method 1) 4. 5 4. 7 Temperature (K) 4. 9 Fig. Typical 4 K-JT behavior during the 50 m. K cooler recycle (method 1 B). 7

5. Coolers integration u Integration completed without any severe discrepancies. 2 K-JT coupled with PT 15 K Integrated 50 m. K hybrid cooler Credit: CEA 4 K-JT with 2 ST J. M. Duval et al. CEC (2015) Cryostat and GSE 8

6. Cryostat 1 cooling down from 300 K to 1. 7 K u Typical cooling profile from 300 K to 1. 7 K 2 ST Start 2 ST 20 W 2 ST 24 W Start GSE cooler, Start PT 15 K 25→ 50 W PT 15 K 2 ST 60 W PT 15 K 100 W → 150 W, Phase Optimization PT 15 K Restarted 4 K-JT 2 K-JT (3 He) GSE 1 GSE 2 (dashed) OCS top ICS 4 K (dashed) PT 15 K 1 st stage PT 15 K 2 nd stage 2 ST 1 st stage 2 ST 2 nd stage 4 K-JT cold finger 2 K-JT cold finger PT 15 K 300 W, T control 2 ST 38 W 2 ST 60 W 2 ST 46 W 4 K-JT 2 K-JT (3 He) Cool down 9

7. JT coolers performance u No apparent degradation in both JT coolers performances l 2 ST 2 nd stage temperature was slightly lower with 62 W after the installation into cryostat 1. In this condition, 4. 3 K was obtained with almost same JT driving power (different compressor balance). The gravitational effect may exists. 4 K-JT heat load 2 ST 1 st 2 ST 2 nd JT coldtip PL PH FL 2 ST JTCL Vacuum Vessel (23 Jun 2017, in Japan) 40. 1 m. W 118. 2 K 18. 4 K 4. 29 K 100 k. Pa 1628 k. Pa 1. 93 81 W 62. 4 W Vacuum Vessel (30 Mar 2017, in France) 40. 2 m. W 109. 3 K 18. 1 K 4. 28 K 100 k. Pa 1652 k. Pa 1. 93 81. 8 W 62. 7 W Cryostat 1 (14 Apl 2017) 39. 9 m. W 96. 0 K 17. 3 K 4. 32 K 103 k. Pa 1554 k. Pa 1. 89 61. 6 W 61. 3 W NL/min l Confirmed the required cooling power. l Cooing power of 19 m. W at 1. 77 K has been measured by PT 15 K precooling temperature of 9. 9 K. 2 K-JT heat Load PT 1 st PT 2 nd JT coldtip PL PH FL PT 15 K JTC PT 90 K / 15 K (6 Jul 2017) 10. 0 m. W 92. 2 K 14. 9 K 1. 72 K 7. 8 k. Pa 541 k. Pa 1. 33 300 W 40. 0 W PT 90 K / 10 K (12 Jul 2017) 19 m. W 92. 2 K 9. 9 K 1. 77 K 7. 2 k. Pa 484 k. Pa 1. 26 300 W 37. 3 W NL/min 10

8. Hybrid cooler recycling (1/2) u Successfully obtained 50 m. K more than 10 cycles. l Hold time of 33 hr 20 min obtained with the recycling time of 9 hr 05 min (~78%) using the nominal operation. l Required cooling power demonstrated with heater. • 0. 4μW at 50 m. K • 14μW at 300 m. K Recycling Observation Sorption pump 4 K-JT 2 K-JT 300 m. K sorption evaporator 50 m. K ADR Recycle start Recycle end l +10 m. W / +3 m. W heat load from 50 m. K hybrid cooler to 4 K-JT / 2 K-JT. l 4 K-JT heat load: 30 → 40 m. W. l 2 K-JT heat load: 4 → 7 m. W. l Successfully operated with method 1 B (max interface temperature regulation). 11

8. Hybrid cooler recycling (2/2) 25 Oct 2017 u Accelerated recycling. l Shorter recycling time by higher heat load with lower max sorption temperature. l 4 numbers of trials. l Duty cycle of 85% (90% possible). T(K) Sorption pump 4 K-JT 2 K-JT 300 m. K sorption evaporator 28 Feb 2018 50 m. K ADR l +20 m. W / +3 m. W heat load from 50 m. K hybrid cooler to 4 K-JT / 2 K-JT. l 4 K-JT heat load: 20 → 40 m. W. l 2 K-JT heat load: 4 → 7 m. W. l Successfully operated with method 1 B (max interface temperature regulation). 12

Summary u Successful design of test cryostat l Integration validated without severe problems. l Good heritage for DCS and flight models. l Efficient tool for coolers characterization. u JT coolers performance l 1 st time to integrate and operate two JTs. l Many operating points measured. l Cooling performance with different precooling temperature. u 300 K – 50 m. K cooling operation l Successful coupling of coolers. • 2 K-JT and PT 15 K • Hybrid cooler and JT coolers l Efficient operation. • 33 hours hold time measured. • 9 hours recycling time. • Accelerated cycle 13

u The transports, installations and performance tests have been performed successfully without critical schedule delay. 2017/2018 Jan 4 K-JT test (VV, in JP) SHI/ JAXA 4 K-JT trans. JAXA/ SHI 4 K-JT test (VV) JAXA 4 K-JT integration CEA/ SHI/ JAXA 4 K-JT test JAXA 2 K-JT trans. JAXA/ SHI 2 K-JT integration CEA/ SHI/ JAXA 2 K-JT test (4 He) JAXA/ SHI 3 He gas purification JAXA/ SHI 2 K-JT test (3 He) JAXA/ SHI Feb Mar Apr May Jun Jul Aug Sep Japan Oct Feb Plan Result France Hyb. C test Hyb. C add. test VV: using vacuum vessel for transport 14 Mar