Developing a low temperature Coulomb Blockade Thermometer

We are working to develop a Coulomb Blockade Thermometer (CBT) that operates from 1K down to 30mK. While the secondary thermometers usually used can lose calibration, a CBT is a primary thermometer and would be useful for getting accurate temperature measurements. CBTs are composed of arrays of tunnel junctions designed so that the charging energy is less than the thermal energy of the electrons. The temperature can be determined by analyzing the array’s conductance as a function of the voltage placed across it. We succeeded in building a CBT and performed measurements with it using lock-in techniques. However, a high junction failure rate has hampered our efforts, and it will have to be solved before we can use the CBTs effectively. Acknowledgments This project has proved to be a great learning experience – I have gained many skills that will surely be useful in graduate school. Undoubtedly, the most important of them is patience! In the process, I was able to work with a great group, and I owe them much for their help. First, I must thank Dr. Rimberg. Due to circumstances beyond my control, I had t