Level 1 of 5 · field of view ≈ 1 m
Cryostat
A dilution refrigerator: six temperature stages from 300 K down to about 10 mK, with every control and readout line threaded through them.
Temperature stages
StageCoolingn̄ at 5 GHz
Cooling power falls by a factor of about a million from the 4 K stage to the mixing chamber. Every wire is a heat leak budgeted against these numbers.
Thermal noise down a drive line
Source at 295 K1229 photons
20 dB at cold plate0.361 photons
20 dB at mixing chamber3.6 × 10⁻³ photons
Computed from the attenuator formula with the stage temperatures above. Bars are logarithmic.