JES-X320 Electron Spin Resonance Spectrometer

The JES-X320 provides high sensitivity with an easy operation environment.


  • Spectrometer designed to be user friendly
    --High-sensitivity ESR equipped with ultra-low noise microwave source
    --Easy-to-use operation interface under Windows10™
    --Auto-tuned microwave circuit and built-in frequency counter
    --Flexible sequential measurements including randomized values of parameters, e.g. sample temperature, angular rotation, etc.
  • Low noise high stability microwave unit
    The JEOL solid-state Gunn diode element provides long life (20,000 hours or more), stable operation, and high reproducibility
  • High sensitivity cavity
    Cylindrical type resonator TE011 can accommodate larger samples and provides for better modulation uniformity
  • High-homogeneity, high resolution, high stability Electromagnets
    The JES-X320 employs a magnetic field linear sweep circuit based on the magnetic field detection system using a Hall element
JES-X320 Electron Spin Resonance Spectrometer

JES-X3 Available Models

  Pole Diameter Pole Gap Max. Field (T) Homogeneity Sensitivity
JES-X310 15 cm 60mm 0.65 5 x 10-6 5 x 109 spins / 10-4 T
(at 100 kHz modulation)
JES-X320 24 cm 62mm 1.30 5 x 10-6 5 x 109 spins / 10-4 T
(at 100 kHz modulation)
JES-X330 36 cm 75mm 1.40 5 x 10-6 5 x 109 spins / 10-4 T
(at 100 kHz modulation)
Select from 3 Magnets According to Research Requirements

Contact Us

  • Contact your local Sales Representative to schedule an in-person or virtual demo now
    (USA, Canada, Mexico, Brazil)

Learn More

Download the JES-X3 Series product brochure

You can also read an in-depth published article on the history of JEOL NMR and ESR

Key Features

High Sensitivity

Higher sensitivity measurement is feasible by using a Gunn oscillator which supplies a noiseless stable microwave, a TE011 cylindrical cavity with a high Q-value, a large sample volume, and a modulation coil capable of obtaining a homogeneous magnetic field. The ESR spectrum below, obtained for Tempol/ Benzene solution (1 uM), by using a 100 kHz modulation frequency, clearly shows a guaranteed sensitivity of 5.0x109 spins/0.1 mT.

ESR High Sensitivity

High Resolution

The magnet polepiece is made of a high-purity material which is precision machined and provides for a homogeneous magnetic field. Ring shims are attached to polepiece surfaces to allow use of a wide high-homogeneity range. In order to obtain high resolution, a cavity made of materials without impurities such as ferromagnetic material, a highly stable power supply for the magnet, and stable magnetic field modulation are required, besides the magnet with a homogeneous magnetic field.
ESR High Resolution
The JES-X320 is well designed to meet these requirements. Shown above is an ESR spectrum of Coppinger radical. The smallest split coupling of t-butyl base 4.7 uT, and its split shows a 2.35 uT resolution.

High Stability

In order to obtain data with excellent reproducibility, a stable and linear magnetic field is necessary. To obtain a stabilized static magnetic field, the JES-X320 employs a Hall element with good linearity, and the entire Hall element is thermally controlled to guarantee a magnetic field stability as high as 5 x 10-6 / 0C・h. The high stability shown is 100 times superimposed ESR spectra of perylene cation radical with ±0.1 mT magnetic field sweep in one hour measurement.

ESR High Stability

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