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Bruker EMXplus EPR Spectrometer

Instrument types

The Bruker EMXplus Spectrometer System uses EPR (Electron Paramagnetic Resonance) which is a very useful and powerful technique for studying samples that are paramagnetic (i.e. have unpaired electrons). Applications of EPR include:

  • Kinetics of radical reactions
  • Redox processes
  • Metal ions
  • Defects in crystals
  • Polymer properties
  • Effects of ionizing radiation
  • Spin labeling and spin trapping
  • Antioxidants
  • Enzyme and carcinogenic reactions
  • and many more

Spectrometer Features:

  • Microwave Frequency Range: CW X-Band (9 - 9.8GHz)
  • X-Band Solid State Ultra Low Noise Microwave Bridge
    • Max leveled source output: 200 mW
    • Max. attenuation: 60 dB
    • Tuning range: 60 MHz
    • Integrated Bridge Controller w/ real time display for optimizing parameters
  • Digital Ultra High Resolution Hall Field Controller
    • Operating Range: 100 G - 18 kG
    • Sweep Range: up to 0 - 18 kG (0 - 1.8 mT) in one scan
  • High Linearity Modulation Amplifier Module: 500 Hz - 120 kHz
  • High Sensitivity Probehead
    • Q > 15,000
    • Optical window for photactivated experiments
    • Up to 10mm sample tube access
    • Max. modulation amplitude: 20 G
    • Automatic cavity tuning and matching
  • AquaX and Flat Cell accessories for aqueous samples
  • Nitrogen and Helium cryostats for VT and Low T experiments, respectively
  • ENDOR Probehead w/ freqency range of 1 - 100 MHz
  • Programmable Goniometer for aquiring spectra at different orientations of the applied magnetic field with respect to the sample
  • Simulation Software: XSophe

For full specs from the orginal quote click here EPR Specifications


  • Room Temperature
  • Time Scans - for kinetics studies
  • 2D - a second parameter, such as, power or temperature, can be varied
    along with the magnetic field
  • Cryogenic Experiments:
    • Variable Temperature using liquid N2
      Range: 100K - 700K
      Sample Tube Requirements: Max O.D. = 5 mm
    • Low Temperature using liquid He
      Range: 4K - 100K
      Sample Tube Requirements: Only O.D. = 4 mm & 5 mm
  • ENDOR - Electron-Nuclear DOuble Resonance

Advanced notice of 2 weeks must be given to Jaya Nolt and Jerry Hu if cryogenic experiments wish to be performed because cryogens must be ordered and the system has to be prepared/setup.

If ENDOR experiments wish to be performed, please make an appointment with Jaya and/or Jerry.

EPR sample tubes are made out of quartz due to it being free from paramagnetic impurities. NMR tubes can be used if the signal from the sample is strong, however, since they are made out of Pyrex, an iron peak may be seen in the spectra if the sample's signal is weak.

To purchase EPR sample tubes, click on the following link:

Wilmad Labglass - EPR Sample Tubes


Everyone must first be trained for the Room Temperature Experiments before moving on to cryogenic and/or ENDOR experiments. Please fill out the EPR Training Request Form and indicate which experiment(s) you would like to do (room temp, VT w/ liq. N2, or VT w/ Helium) in the comment box.