AIM cryocooler developments for HOT detectors

Abstract

Significantly increased FPA temperatures for both Mid Wave and Long Wave IR detectors, i.e. HOT detectors, which have been developed in recent years are now leaving the development phase and are entering real application. HOT detectors allowing to push size weight and power (SWaP) of Integrated Detectors Cooler Assemblies (IDCA's) to a new level. Key component mainly driving achievable weight, volume and power consumption is the cryocooler. AIM cryocooler developments are focused on compact, lightweight linear cryocoolers driven by compact and high efficient digital cooler drive electronics (DCE) to also achieve highest MTTF targets. This technology is using moving magnet driving mechanisms and dual or single piston compressors. Whereas SX030 which was presented at SPIE in 2012 consuming less 3 W DC to operate a typical IDCA at 140K, next smaller cooler SX020 is designed to provide sufficient cooling power at detector temperature above 160K. The cooler weight of less than 200g and a total compressor length of 60mm makes it an ideal solution for all applications with limited weight and power budget, like in handheld applications. For operating a typical 640x512, 15µm MW IR detector the power consumption will be less than 1.5W DC . MTTF for the cooler will be in excess of 30,000h and thus achieving low maintenance cost also in 24/7 applications. The SX020 compressor is based on a single piston design with integrated passive balancer in a new design achieves very low exported vibration in the order of 100mN in the compressor axis. AIM is using a modular approach, allowing the chose between 5 different compressor types for one common Stirling expander. The 6mm expander with a total length of 74mm is now available in a new design that fits into standard dewar bores originally designed for rotary coolers. Also available is a 9mm coldfinger in both versions. In development is an ultra-short expander with around 35mm total length to achieve highest compactness. Technical solutions and key performance data for AIM's HOT cryocoolers will be presented.

Low SWaP MWIR and LWIR modules with small pixel pitch

“…At the same time suitable miniature cryocooler types are available to exploit SWaP potential of both HOT MWIR and LWIR FPAs. More precise, AIM's family of HOT split linear coolers contains both the single piston members SX020 8 and SX030 9 and the dual piston cooler types SX025 and SX035 10 . Key advantages of these cryocoolers are low audible noise, long cooler life times, shortest detector-dewar length and a high flexibility in the arrangement of the subcomponents due to the split design.…”

Multimodal tuned dynamic absorber for split Stirling linear cryocooler

“…For compactness, the expander and compressor may be side-by-side packaged; in this case expander-induced vibration export may produce moment about the payload center of gravity producing excessive angular response resulting in line-of-sight jitter, thus the secondary matched TDA may be advised. Different theoretical and practical aspects of using TDA in application to split linear Stirling cryocooler were discussed by the authors in [6][7][8][9][10][11][12][13][14].…”

“…In the recent years major vendors of cryogenic coolers, such as DRS, AIM, L3, Cobham and Ricor developed and fielded new models of so called SWAP (Size, Weight and Power) linear cryocoolers. It is worth noticing that DRS [1,2], L3 [3] and Cobham [4] are following the traditional "dual-piston" compressor design approach, while Ricor [5][6][7][8][9][10][11][12] and AIM [13,14] revised this concept in a favor of "single-piston" approach offering lower SWAP along with better reliability. This decision is substantiated by accounting for the relatively high driving frequency resulting in lower vibration export due to small strokes and low weight of moving assemblies.…”