A new Q-band EPR probe for quantitative studies of even electron metalloproteins

Existing Q-band (35 GHz) EPR spectrometers employ cylindrical cavities for more intense microwave magnetic fields B1, but are so constructed that only one orientation between the external field B and B1 is allowed, namely the B perpendicular B1 orientation, thus limiting the use of the spectrometer to measurements on Kramers spin systems (odd electron systems). We have designed and built a Q-band microwave probe to detect EPR signals in even electron systems, which operates in the range 2 K