Introducing "PinQ": our new cryogenic forced oscillation apparatus

 With our funding of a study on the dislocation and strain dependence of attenuation (also called inverse Q) and the arrival of Dr. Hatsuki Yamauchi to work on the project, we decided to assess our machine capabilities. It became quite clear that our original idea of using the biax would not be a good idea because it is not stiff enough (which is part of why it is a great friction apparatus). So we needed to create a new apparatus. Yamauchi-san and I had both worked on a great apparatus in Japan, that had high strain resolution and very precise application of stress. That apparatus ran at room temperature or slightly higher temperatures. So we needed to adapt that design (the "TKY-style" apparatus) for cold temperature work. 

2021 and 2022 were bad times for purchasing parts and it seemed every component was on back order and seriously delayed. The machinist also had a back log. Whatever could be done by us, we did.

First big task was to find a nice stiff, hopefully pre-existing, frame. Ted found one (as he does) but it was looking very dirty and not the right color at all. Hatsuki suggested a paint job and new color scheme. And thus the frame was painted a bright beautiful shade of pink.

Eventually the laser displacements meters (and their stage motors), the screw jack, the stepper motor, the piezo-electric actuator and the rotational base all arrived and Hatsuki assembled it all on the stone table Ted had acquired from somewhere.

Copper coils connected to circulating fluid created the cryostat, with a bellows at the top to prevent condensation but not affect the sample testing. The only thing that it needed now was a brain.

This is when we scheduled John Leeman of Leeman Geophysical to come out. Over the course of a few day visit he got us all set up with a LabView control system that would drive the multi-day experiments, monitor temperatures and all other feedbacks, and record the calibrated data.

We then installed a shelf to hold all the control boxes, etc. Here is the resulting set up.

In the Review of Scientific Instruments paper that followed, Dr. Yamauchi provided all of the error corrections and calibrations and describes the working range of the apparatus. Many exciting papers to follow!