Noise Figure significantly decreases as the Temperature Decreases.
To optimize Noise Temperature or Noise Figure the LNA design must be optimized to minimize any internal heating. Power Supplies and Regulators need to be external to the Amp. The LNA should be designed and operated with the lowest possible DC Input Power. Example: When properly designed, a Room Temperature LNA with a NF of 0.45 dB may decrease to 0.03 dB at 4K.

What Customers use Cryogenic Low Noise Amplifiers?
Radio Astronomy: The technique in Radio Astronomy is to use Microwave Radiometers with Very Large Antenna Dishes. A Microwave Radiometer are extremely sensitive receivers. They measure energy emitted at Millimeter-wave Frequencies. The Lower the NF the more sensitive the receiver. The Larger the Dish the Higher the Gain for more sensitivity.

Quantum Computing: The next generation Quantum processors operate in Cryostats. The temperatures are as low as 4K to 10mK.
Quantum Computing needs to be in an environment where all noise is eliminated. The Cryostats operate at a temperature where all noise is eliminated from the outside environment. To achieve these temperatures all devices, need to have the lowest loss, the lowest Noise Temperature, the smallest size, the lowest DC power, and the best Thermal Conductivity.

Quantum Microwave is the US and Canada Distributor for Low Noise Factory. The Industries Lowest Noise Cryogenic LNA’s. When performance matters Quantum Microwave and Low Noise Factory deliver.