Heated Zener Reference And Josephson Junction Array Comparisons - Keithley 2182 User Manual

Heated Zener Reference and Josephson Junction Array comparisons

The performance of a Heated Zener Reference can be analyzed by comparing it to a
Josephson Junction (JJ) Array using both channels of the Model 2182. In a cryogenic
environment, the JJ Array provides an output voltage in precise, stable 175µV steps.
The test circuit for this application is shown in
Channel 1 of the Model 2182 measures 0V ±10µV. The null condition indicates that the Heated
Zener Reference voltage is the same as the JJ Array voltage. Channel 2 of the Model 2182 is
used to determine the exact step that the JJ Array is on. Channel 1 can then be monitored to study
noise and drift characteristics of the Heated Zener Reference.
Figure 2-14
Heated Zener characterization
Heater
Voltage and Temperature Measurements
2182
CH 1
HI LO
V
HI
2182
Zener V
CH 2
LO
Figure 2-14. The JJ Array is adjusted until
Josephson
Junction
XX
Array
2-27