Heterodyne Spectrometer

The instrument is based on the 12.5 T superconducting magnet and is configured as a quasi-optical device employing heterodyne detection that results in better sensitivity. In a heterodyne, the EPR signal is not directly observed at the frequency of the incident microwaves, but rather is mixed with a second microwave frequency to generate a difference frequency of several GHz. The resulting low-frequency signal is further amplified and processed. The apparatus is equipped for ENDOR operation. Available frequencies are 120, 240 and 336 GHz. The sample temperature can be controlled over the range of 3K to 400K.

Above: The heterodyne spectrometer uses a 12.5 tesla superconducting magnet (lower left).

Below: Some of the electronics of the heterodyne instrument.

Related Links

• A multifrequency high-field pulsed electron paramagnetic resonance/electron-nuclear double resonance spectrometer by by G. W. Morley, L. C. Brunel and J. van Tol, Review of Scientific Instruments 79, 064703, 2008.
• A quasioptical transient electron spin resonance spectrometer operating at 120 and 240 GHz, by J. van Tol, L. C. Brunel and R. J. Wylde, Review of Scientific Instruments 76, 074101, 2005.

For more information, contact Hans Von Tol.