Balancing Thermal Transmission & Electric Field Control in a Cryostation

Posted 24 September, 2015

This was an exciting and challenging month at Montana Instruments as we started shipping our first Cryostation C2 systems. This next generation of our flagship product has been over a year in the making with the team working diligently to refine even the smallest details. With a focus on continuous improvement, we re-engineered aspects of the original design to respond to the evolving needs of the research community, such as isolating vibrations on the table and increasing usability with a new bezel shape that provides easier access to the sample.

MI team photo C2 shipment

Members of the Montana Instruments team share a toast as the first Cryostation C2 is shipped

One of these first systems was a complex unit that presented a few engineering challenges. Beyond ensuring our customer's satisfaction, our ultimate goal was to create a system that would perform as needed to facilitate experimental results. The researcher's application required creating a high-voltage electric field (1000V) around a single crystal, with laser transmission in the field and cross-field directions, while isolating another crystal as a "control" sample. They needed optical access to both samples simultaneously, from all four sides. After testing the sample, we also discovered significant pressure on the sample would be required for good thermal transmission. To top it off, the customer needed to reach 3.8K for this crystal behavior to work out, otherwise the system was useless!

To accomplish this, the system needed to have a dual sample mount, dual transmission windows, custom high-voltage MHV connector side panels, high-voltage Kapton-insulated stainless steel wires, custom brass electrode plates, custom Teflon structures for electrical insulation, a custom made Sapphire bridge for supporting the electrified sample (while conducting thermally and isolating electrically), and a custom tower press to apply force to the sample without hindering horizontal views.

C2 MHV connectors

Figure 1: Detail of MHV connector side panels.

C2 custom electric field

Figure 2: Detail of internal components.

Once built, our original thermal tests turned out to be problematic and the temperature on the electrified sample was too high. With important research at stake, it was critical for us to make it work. The team went back to the assembly and started to diagnose the issue. At first, they corrected a simple "touch" that brought the electrified sample down to 3.65K, below spec. However, still not satisfied and pushing to make it even better, they put a few more brains together and came up with a more robust solution involving eliminating radiation through the top window and re-engineering the overhead pressure bridge with a flexible thermal link strap. The result? A base temperature of 3.39K on the electrified sample and 3.21K on the "control" sample, which was over 10% better than the customer's specifications.

It took our team less than 2 days to calculate, design, build, and implement these solutions, which just goes to show how our engineers thrive on tough challenges. It's a type of commitment driven by the desire to exceed customer expectations and an underlying passion for helping researchers make new discoveries. While we can't solve every problem, we will listen, and we will try. If it's possible, our team will find a way. That's part of the spirit here at Montana Instruments.