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Publications - Thales Cryogenics

SPIE-DSS 2017 – How to manage MTTF larger than 30,000hr on rotary cryocoolers

The cooled IR detectors are used in a wide range of applications. Most of the time, the cryocoolers are one of the components dimensioning the lifetime of the system. Indeed, Stirling coolers are mechanical systems where wear occurs on millimetric mechanisms. The exponential law classically used in electronics for Mean Time to Failure (MTTF) calculation cannot be directly used for mechanical devices. With new applications for thermal sensor like border surveillance, an increasing reliability has become mandatory for rotary cooler. The current needs are above several tens of thousands of continuous hour of cooling. Thales Cryogenics made specific development on that topic, for both linear and rotary applications. The time needed for validating changes in processes through suited experimental design is hardly affordable by following a robust and rigorous standard scientific approach. The targeted Mean Time to Failure (MTTF) led us to adopt an innovative approach to keep development phases in line with expected time to market. This innovative approach is today widespread on all of Thales Cryogenics rotary products and results in a proven increase of MTTF for RM2, RM3 and recently RM1. This paper will then focused on the current MTTF figures measured on RM1, RM2 and RM3. After explaining the limit of a conventional approach, the paper will then describe the current method. At last, the authors will explain how these principles are taken into account for the new SWaP rotary cooler of Thales Cryogénie SAS.

Keywords: Cryogenics, MTTF, Reliability, Accelerated ageing, Stirling, Cooler, IR detector, RM2

Original publications: Proc. SPIE 10180

Thales Cryogénie S.A.S. France: Jean-Marc Cauquil, Cédric Seguineau*, Jean-Yves Martin, Sébastien Van-Acker

Thales Cryogenics B.V. Netherlands: Tonny Benschop

SPIE-DSS 2017 – Tactical versus space cryocoolers: a comparison

In recent years, several space cryocooler developments have been performed in parallel at Thales Cryogenics. On one end of the spectrum are research programmes such as the ESA-funded 30-50 K system developed in cooperation with CEA and Absolut System and the LPT6510 cooler developed in cooperation with Absolut System. On the other end of the spectrum are commercial designs adapted for space applications, such as the LPT9310 commercial coolers delivered for JPL’s ECOSTRESS instrument and the LSF9199/30 SADA-compatible cooler delivered for various space programmes at Sofradir. In this paper, an overview is presented of the latest developments regarding these coolers. Initial performance results of the 30-50K cooler are discussed, pending developments for the LPT6510 cooler are presented, and the synergies between COTS and space are reviewed, such as design principles from space coolers being applied to an upgraded variant of the COTS LPT9310, as well as design principles from COTS coolers being applied to the LPT6510 for improved manufacturability.

Original publication: Proc. SPIE 9821

R. Arts, J. Mullié, H. Leenders, G. de Jonge, T. Benschop Thales Cryogenics B.V. (Netherlands)

SPIE-DSS 2017 – RMs1: Qualification results of the rotary miniature Stirling cryocooler at Thales Cryogenics

The trend for miniaturized Integrated Dewar and Cooler Assemblies (IDCA) has been confirmed over the past few years with several mentions of a new generation of IR detector working at High Operating Temperature (HOT). This key technology enables the use of cryocooler with reduced needs of cryogenics power. As a consequence, miniaturized IDCA are the combination of a HOT IR detector coupled with a low-size, low-weight and low-power (SWaP) cryocooler. Thales Cryogenics has developed his own line of SWaP products. Qualification results on linear solution where shown last year. The current paper focuses on the latest results obtained on RMs1 prototypes, the new rotary SWaP cryocooler from Thales Cryogenics. Cryogenic performances and induced vibrations are presented. In a second part, progress is discussed on compactness and weight on one side, and on power consumption on the other side. It shows how the trade-off made between weight and power consumption could lead to an optimized solution at system level. At least, an update is made on the qualification status. Keywords: Cryogenics, Rotary Stirling Cooler, IR Detector, HOT, SWaP

Original publication: Proc. SPIE 10180

Thales Cryogénie S.A.S. France: Jean-Yves Martin, Cédric Seguineau*, Sébastien Van-Acker, Mikel Sacau, Julien Le Bordays, Thierry Etchanchu, Christophe Vasse, Christian Abadie, Gilles Laplagne,

Thales Cryogenics B.V. Netherlands: Tonny Benschop