Cryocoolers are needed in modern high-performance infrared cameras to establish and maintain the cryogenic temperature of infrared focal plane arrays. Attollo has a number of cryocooler development efforts ranging from low SWaP linear microcoolers for HOT MWIR sensors to high lift, high reliability coolers for 80K operation. In the case of cryocoolers designed for HOT MWIR applications, Attollo is also developing low-cost designs to address the attritable platform market. Attollo will present an overview of these design programs and data on the performance of initial units.
Unmanned airborne and dismounted soldier capability requirements continue to push for reduced size, weight, and power (SWaP) and high sensitivity infrared (IR) imaging in applications that were not previously practical. In response to these needs, Attollo Engineering has developed a 1280x1024, 5μm pixel pitch cooled mid wavelength infrared (MWIR) sensor that pushes the envelope in pixel pitch in addition to a 1280x1024, 10μm pixel sensor dual band sensor with additional sensitivity in the short wavelength infrared (SWIR) in order to exploit SWIR phenomenology including laser see spot functionality. Both of these sensors offer MWIR sensing capabilities but are also able to leverage aspects of Attollo’s detector design to enable SWIR sensing to varying degrees. This class of small pixel cooled, single and dual band IR sensor technology represents advancements in all aspects of the sensor’s design and development, and we will discuss the innovations made at Attollo to enable this capability including epitaxial detector design based on III V compound semiconductors, detector array and focal plane array fabrication, design of a low noise, dual band CTIA/DI readout integrated circuit (ROIC), vacuum dewar packaging, and electronics and firmware design. In this paper we will present on the status of high definition small pixel pitch MWIR and dual band SWIR/MWIR imaging technology at Attollo as it relates to these sensors including design and measurement data and imaging.
We report the development and initial testing of the Lockheed Martin first-article, single-stage, compact, coaxial, Fast Cooldown Pulse Tube Microcryocooler (FC-PTM). The new cryocooler supports cooling requirements for emerging large, high operating temperature (105-150K) infrared focal plane array sensors with nominal cooling loads of ~300 mW @105K @293K ambient. This is a sequel development that builds on our inline and coaxial pulse tube microcryocoolers reported at CEC 20137, ICC188,9, and CEC201510. The new FC-PTM and the prior units all share our long life space technology attributes, which typically have 10 year life requirements1. The new prototype microcryocooler builds on the previous development by incorporating cold head design improvements in two key areas: 1) reduced cool-down time and 2) novel repackaging that greatly reduces envelope. The new coldhead and Dewar were significantly redesigned from the earlier versions in order to achieve a cooldown time of 2-3 minutes-- a projected requirement for tactical applications. A design approach was devised to reduce the cold head length from 115mm to 55mm, while at the same time reducing cooldown time. We present new FC-PTM performance test measurements with comparisons to our previous pulse-tube microcryocooler measurements and design predictions. The FC-PTM exhibits attractive small size, volume, weight, power and cost (SWaP-C) features with sufficient cooling capacity over required ambient conditions that apply to an increasing variety of space and tactical applications.
We report the development and initial testing of the Lockheed Martin first-article, single-stage, compact, coaxial, Fast Cooldown Pulse Tube Microcryocooler (FC-PTM). The new cryocooler supports cooling requirements for emerging large, high operating temperature (105-150K) infrared focal plane array sensors with nominal cooling loads of ~300 mW @105K @293K ambient. This is a sequel development that builds on our inline and coaxial pulse tube microcryocoolers reported at CEC 20137, ICC188,9, and CEC201510. The new FC-PTM and the prior units all share our long life space technology attributes, which typically have 10 year life requirements1. The new prototype microcryocooler builds on the previous development by incorporating cold head design improvements in two key areas: 1) reduced cool-down time and 2) novel repackaging that greatly reduces envelope. The new coldhead and Dewar were significantly redesigned from the earlier versions in order to achieve a cooldown time of 2-3 minutes-- a projected requirement for tactical applications. A design approach was devised to reduce the cold head length from 115mm to 55mm, while at the same time reducing cooldown time. We present new FC-PTM performance test measurements with comparisons to our previous pulse-tube microcryocooler measurements and design predictions. The FC-PTM exhibits attractive small size, volume, weight, power and cost (SWaP-C) features with sufficient cooling capacity over required ambient conditions that apply to an increasing variety of space and tactical applications.
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