Cryogenic Temperatures

As most of the instruments are designed to observe extremely faint infra red sources, the detectors must be cooled to very low temperatures and must be well shielded from the environment which is glowing in the same wavelength range. Furthermore, some detectors have to be cooled even further (to below 1 Kelvin) to achieve the exquisite sensitivity demanded by astronomers.

 

Cryogenic systems

We are experienced in the design and implementation of cryogenic systems capable of achieving temperatures of less than 1 Kelvin (-272°C). Some are based on liquid cryogens such as nitrogen and helium and some are based on pulse tube coolers and other refrigeration engines. Our instruments often have significant distances between the detectors and the source of cooling, and we are therefore experts in designing thermal links and contacts operating at temperatures from 50 millikelvin upwards.

 

Shielding

The ATC is expert in designing housings to shield the sensitive parts of the instrument from both the environment and the heat loads generated by the internal electronics.

 

Electronics

All internal electronics produce heat loads in the instrument which must be properly managed. ATC electronics engineers are specialists in minimising the disruption and managing it where necessary by using special cabling and shielding.

Mechanisms and Robotics

As mentioned, designing and making mechanisms to operate at low temperatures is complicated by the facts that material properties are often not well understood in the cryogenic regime and that standard lubricants freeze out and are useless. ATC mechanical engineers have years of experience in building robust and reliable cryo-mechanisms.

 

Material Properties

Good engineering requires reliable data on material properties such as thermal conductivity and mechanical strength. Such data can be hard to obtain for the cryogenic regime, and is often unavailable. At the ATC we have a large library of data, and the expertise to correctly interpret and apply it for design purposes (for example, variation between samples is often huge at cryogenic temperatures). Where data cannot be obtained, we have the facilities to make our own measurements. We also have the ability to accurately model thermal performance of complex instruments.