GB1174108A - Spectrometer, particularly for Electronic Paramagnetic Resonance - Google Patents

Abstract

1,174,108. Gyromagnetic resonance spectrometers. CARL ZEISS JENA, VEB. March 10, 1967, No. 11299/67. Heading G1N. In an electron paramagnetic resonance spectrometer comprising a frequency modulated U. H. F. source 1 and a reflection cavity resonator 17 for the sample being investiaged, the phase of the reference signals for two phase-sensitive rectifiers 21, 23 is automatically controlled by an electrically variable phase shifter 19 controlled by a signal obtained from the output of the phase-sensitve rectifier 23 via an amplifier 22 and a further phasesensitive rectifier 18. The output of phasesenstive rectifier 23 is also fed, via a switch 24, to a signal recorder, which is preferably digital, or, via a variable gain amplifier 20, to the cavity 17 for automatic bridge balancing. The phasesenstive rectifier 21 receives its reference signal via a 90 degree phase shifter 11 and its output is fed, via a variable gain amplifier 16, to stabilize the frequency of the U. H. F. source 1 to the resonance frequency of the cavity 17. A frequency conversion stage (not shown) may preceed the detection stage. In use, the resonance spectrum is repeatedly scanned and the individual spectra summed. In the intervals between scans, an automatic zero balance of the bridge takes place. Alternate scans may be in opposite directions. The magnetic field may be stabilized on a nuclear magnetic resonance line during the intervals between scans and by induction voltage stabilization during scans.