Quantitative electron paramagnetic resonance (EPR) spectrometry with a TE104 double rectangular cavity Part 1. A simple alignment procedure for the precision positioning of the sample

The Bruker TE104 double rectangular cavity is commonly utilized for quantitative electron paramagnetic resonance (EPR) spectrometric measurements. The sample, together with an appropriate standard, can be studied simultaneously within such a cavity under identical states of machine tuning and parameter settings. However, even under such conditions, there still remain sources of error arising from sample size, shape and positioning of the sample tube within the cavity. In this paper such sources of error have been investigated and a procedure to minimize the errors by precision insertion of the sample tubes within the TE104 cavity is described.