The bruker high-frequency-EPR system

Field and frequency modulated sub-THz electron spin resonance spectrometer

“…Significant developments of high-field quasi-optical ESR are ongoing, 32,33,[36][37][38][39][40] where cw ESR has evolved up to f hν = 750 GHz 41 and free electron lasers (FEL) can provide highest irradiation power (several kW) in pulsed or quasi-cw high-field ESR. [42][43][44][45] However, these spectrometers are highly specialized and operate in one dedicated high-field environment, 41 and a very recent commercial system provides a high ESR sensitivity but narrow (0.2 T) field sweep range.…”

High-Frequency EPR Instrumentation

“…At lower frequencies , it has been demonstrated that the resonator cylinder itself can be formed from a ''ribbon coil'' [58]. It should be noted also that at W-band frequencies a split pair magnet can be used, so that the TE 011 resonator can be oriented vertically, thus enabling top loading of the sample [25,26].…”

“…By minimizing the inductive contact between the main and sweep coils, some components of the non-linearity can be suppressed. The field hysteresis can be minimized by letting the magnet power supply use ''current jumps'' at the start and end of a sweep [25,26]. In the Bruker W-band system, the magnetic field is calibrated for a multiple of sweep rates using an NMR gaussmeter in the free bore of the magnet.…”

“…4b, since it allows the pulse forming and detection to be performed at the IF frequency of 9 GHz for which the pulsed X-band bridge can be used. In this way, a W-band system can be obtained as an upgrade to an X-band spectrometer [25,26]. In practice, the difference between designs in Fig.…”

“…CW and pulsed EPR as well as ENDOR at 95 GHz (W-band) was realized for the first time by Schmidt et al [19][20][21] and Möbius et al [22][23][24]. In 1996, the Bruker company introduced the first commercial pulsed (and CW) EPR spectrometer at 95 GHz [25,26]. Further developments in millimeter-wave (mm-wave) components at W-band allowed for improvements in excitation power and detection sensitivity [27].…”