The homebuilt 180 GHz Spectrometer

Since 1998, a spectrometer has been developed with an operating frequency of 180 GHz and corresponding magnetic fields of 6.4 Tesla.

Two different setups have been developed: A transmission mode setup working without a cavity and a setup working with a cylindrical closed type cavity . This is the highest frequency worldwide used in conjunction with a cylindrical cavity.

The cryogenic Teslatron H magnet system provided by Oxford Instruments consists of two superconducting coils. One of them produces a static magnetic field in the range of 0 - 7 Tesla and is normally set to 6.422 Tesla, corresponding to 180 GHz for g=2. To reduce liquid helium consumption, the current leads can be replaced by a short plug. The second superconducting coil serves as a sweep coil and allows to sweep over a range of +/- 80 mT. The homebuilt power supply for the sweep coil is connected to a PC via the serial port and has a resolution of 18 bit, corresponding to 0.61 µT. The magnet has an inner bore diameter of 74 mm, whose temperature can be controlled between 4 K and roomtemperature.

All EPR - experiments are controlled by an Intel Pentium 200 MHz PC, to which the devices are connected via an IEEE 488 bus. Experiment control and data acquisition is controlled by means of a homewritten program written in LabView.

Here you can see a picture of the spectrometer: