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INTRODUCTION

The word cryogenics literally means production of icy cold.

However, nowadays this term is used as a synonym for the production of low temperatures.

cryogenics is chosen as the field that works below 123 K.

Normal boiling point of most of the gases such as hydrogen,
nitrogen, etc, lies below 123 K.

The area of cryogenics is concerned with the development and
improvisation of systems, processes and techniques that
operate at low temperature.


CRYOGENICS IN SPACE APPLICATIONS:

Sensors used in space applications should be very sensitive to
catch even the weakest signals reaching us from the stars.
Many of these sensors must be cooled to lower temperature to
have the necessary sensitivity.

some of the examples are

Infrared Sensors

Electronics

X-rays


CRYOGENIC LIQUIDS:

Two gases often used in their liquid form as coolant are
Liquid nitrogen
Helium

The boiling point of liquid nitrogen is 77.4 K and triple point
is 63.2 K. Liquid nitrogen is used in many cooling systems.

The boiling point of liquid Helium is 4.224 K. Helium does
not freeze at atmospheric temperature. Only at pressures
above 20 times atmospheric will solid helium will form.

Liquid Helium because of its low boiling point, is used in
many cryogenic systems when temperatures below the boiling
point of nitrogen is needed.

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