The topics of the solicited papers will include, but not be limited to: 

Mechanical Refrigeration, including Stirling, Pulse-Tube and JT Types 

All mechanical types using gaseous or liquid refrigerants for their refrigeration cycles will be discussed. Today, mechanical cryocoolers, mainly Stirling cryocoolers are the predominant technology to cool high performance IR sensors. These refrigerators have been employed for this purpose for more than 40 years and have been continuously improved over time. State-of-art Stirling cryocoolers offer outstanding thermal efficiency for lowest power consumption and - especially linear coolers – have very long life. The life is in most cases significantly higher than what is needed by the application. The continuous increase in detector operating temperature (HOT detectors) is the driver to significantly improve size, weight and power (SWaP) of IR cryocoolers. The increase in detector operating temperatures is expected to enable entirely new concepts of refrigerators like those of MEMS type. 

Optical Refrigeration 

Optical refrigeration is a rapidly emerging solid-state cooling technology. In this technology, heat is removed from a cooling element when it absorbs laser light at one frequency and emits it at a higher frequency. This well-known optics phenomenon, called anti-Stokes fluorescence, has been exploited in laboratory experiments to cool certain doped crystals from near room temperature to 91 K. This temperature is far below what can be achieved with any other solid state cooling mechanism. Lately, use of semiconductors as cooling elements has shown great potentials. Current R&D efforts focus on materials research, to achieve lower temperatures and higher efficiencies, and on cooler development, to create optical refrigerators for cryogenic sensors and other devices. The special advantages of solid-state optical refrigerators are that they generate no vibrations and have no moving parts that can shorten the cooler lifetime. 

Thermo-Electric Refrigeration 

The operation of Thermo-Electrical (TE) refrigerators, also known as Peltier coolers, is based on physical principles discovered in the early 1800’s. Commercial TE coolers became available in the late 1950’s. An electric current flowing continuously in a closed circuit made up of two dissimilar metals or semiconductors will cause energy to flow between the two junctions. The lowest temperature achieved by multi-staged TE coolers is about 170 K. New materials have shown potential for cooling to much lower temperatures. Efforts are also being made to investigate whether TE coolers can offer advantages over mechanical coolers for operating temperatures above 170 K. This would have an impact on design of infrared systems based on HOT photon detectors. 

Cooler–Detector Integration 

There is a need to develop optimal integration and packaging of the refrigerator with the device to be cooled, like for the forthcoming HOT Integrated Detector Dewar Cooler Assemblies (IDDCA). Minimizing heat inflows and integration losses will result in improvement of SWAP indices and reliability. More attention needs to be paid to better heatsinking and reduction of noise and vibration signature for such IDDCAs as standalone units and on the system level. These efforts will improve the IDDCA reliability and lead to reduction of ownership costs and down times. 

Control Electronics 

The complete refrigeration system fundamentally consists of the thermodynamic device (e.g., any of the tri-technologies) and the electronics to drive the device. Even the simplest of applications require a power source and a somewhat precision temperature control servo. Additional controls are often required, particularly for mechanical coolers. As part of an overall thermodynamic system, power conversion efficiency is paramount. Electromagnetic interference (EMI) and compatibility (EMC) requirements also tend to drive the design, particularly for the military applications of primary interest. However, the electronics are often overlooked during the design cycle in favor of the refrigeration device, resulting in suboptimal system-level performances. Of interest are papers that address the system-level benefits to the user achieved by the development of advanced electronics capabilities in the areas or power efficiency, EMI/EMC, controls, packaging, etc.