SQUIDs - Low Temperature Laboratory

LLNL Axion Detector
• Current system noise temperature: T S = T + T N ≈ 3.2 K
Cavity temperature: T ≈ 1.5 K
Amplifier noise temperature: T N ≈ 1.7 K
• Time to scan the range of frequencies from f 1 to f 2 :
τ(f 1 ,f 2 ) ≈ 4 x 10 16 (T S /1 K) 2 (1/f 1 –1/f 2 ) sec
For f 1 = 0.24 GHz, f 2 = 2.4 GHz: τ ≈45 years
• Note: There is only a factor of 2 to be gained in T S by reducing T
unless T N is also reduced.