Designing, Making and Testing Sample Holder for Electron Paramagnetic Resonance

Electron paramagnetic resonance (EPR) is a spectroscopic tool used to study properties of materials with the presence of unpaired electrons widely used in Physics, Material Science, Chemistry and Biology. EPR works by shining EM radiation and applying external magnetic field into sample material. By detecting reflected EM radiation, EPR allows to observe the behavior and local environment of electrons. However, measuring liquid tends to cause a spurious result because of light passing through sample liquid and reflecting at the bottom of sample holder. It is because EM radiation acquires some phase as it passes through the sample before being measured by the detector. In addition, sample with a high concentrations or large volume cause refractive broadening, which makes a large change in the refractive properties. My goal of this project is designing, making and testing new sample holders geometries which allows us to be able to measure liquid sample with least spurious effect in the continuous-wave EPR. First, I designed multiple different sample holders using SolidWorks and made sample holders following the designs from Teflon rod in physics machine shop. Sample holders were characterized by CW-EPR with a standard sample and performance judged based on high amplitude with low noise and no distortion of signal lineshape. We find that by altering the geometry of the bottom surface we were able to observe changes in both signal amplitude and quality.