Field Emission Cryo-electron Microscope

Quick and easy to operate for high-contrast and high-resolution images.

CRYO ARM™ 300 II Field Emission Cryo-electron Microscope
1.29Å structure of mouse apo-ferritin obtained by Fujita et al. on the CRYO ARM 300 at Spring8 (Japan)
Cryo-electron microscopy (cryo-EM) has taken enormous flight in recent years. Atomic level structural analysis of viruses and proteins derived by cryo-EM using SPA workflows requires high stability hardware and software. JEOL proudly announces its latest offering in cryo-TEMs to facilitate this development in cryo-EM with the CRYO ARM™ 300. The CRYO ARM™ 300 achieves unprecedented resolution and stability thus allowing for the automatic and unattended acquisition of image data for Single Particle Analysis. Figure shows the 1.29Å structure of mouse apo-ferritin obtained by Fujita et al. on the CRYO ARM 300 at Spring8 (Japan).

Automated specimen exchange system

The system is composed of an autoloading specimen stage cooled to liquid nitrogen temperatures and a cryo-storage device for long-term storage of up to 12 frozen-hydrated specimens. Liquid nitrogen is automatically supplied to both the stage and storage system as required. The autoloader allows loading and retrieval of up to 4 grids at a time without impacting the remaining samples in the cryo-storage device. Specimens are stored and labeled using a unique system fully transparent to the operator. These unique capabilities enable beamline-like scheduling of microscopy.

Cold field emission gun (Cold FEG)

cold FEG produces a high-brightness electron beam with a very small energy spread
The cold FEG produces a high-brightness electron beam with a very small energy spread, thus offering high temporal coherency. In addition, spatial coherence is improved resulting in the CRYO ARM™ 300 achieving superior resolution and contrast compared to any 300 kV cryo-TEM currently on the market.

In-column energy filter (Omega filter)

data with higher contrast due to reduced chromatic aberration
Equipped with an improved in-column energy filter (Omega filter), the CRYO ARM™ 300 acquires energy filtered images and energy loss spectra. Zero-loss imaging with the CRYO ARM™ 300 yields data with higher contrast due to reduced chromatic aberration. The stability of the filter has been greatly improved (see figure). This enables SPA runs that only require 2 adjustments of the zero-loss peak position per 24 hours. Setting up the Omega filter has never been easier with a new Auto Adjust function making sure every user can properly set up the filter for data acquisition.

Single Particle Analysis image acquisition software

The CRYO ARM™ 300 is fully compatible with the JEOL Automated Data Acquisition System (JADAS) and SerialEM (UC Boulder). 

Hole-free phase plate*1

The hole-free phase plate (HFPP) consist of a thin, continuous carbon film placed in the back focal plane of the objective lens, thus providing a substantial improvement in image contrast of frozen-hydrated specimen. Manufacturing of the HFPP uses a unique methodology resulting in robust and reliable performance at reasonable prices.

Zero Fringe Illumination*2

CRYO ARM 300 can be outfitted with so-called Köhler illumination
The CRYO ARM 300 can be outfitted with so-called Köhler illumination, resulting in a marked reduction of the fringes at the edge of the beam. This in turn allows using a narrow (parallel) electron beam when images are taken using Coma Free Image Shift (CFIS), or beam/image shift, inside a single hole in SPA runs, or even across holes in the quantifoil (see figure).

Auto adjustment functions*3

Auto focus, auto coma-free alignment, auto parallel-beam illumination and other automated adjustments are available, enabling image acquisition under optimum conditions.
*1 & 2: Optional unit. *3: Images acquired with the bottom mount camera are used.

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Sub-2Å Structures: From Holes to Hydrogens

Presented by Jana Ognjenovic, NIH National Cryo EM Program June 2021 - MicroComII 24 Hours of Life Science Program

The CRYO ARM Family of Microscopes

Dr. Jaap Brink, JEOL

High Resolution on the CRYO ARM: Past, Present and Future

Dr. Jana Ognjenovic, NIH

Recently Published Papers

Key Features

Increased productivity for cost effectiveness

Quick Collection

The JEM-3300 CRYO ARM™ 300 II achieves high speed data acquisition by combining beam shift with precise specimen stage movement. The excellent beam control of this system minimizes the beam tilt that causes coma aberration, even with beam shift. Hence, the throughput can be increased without degrading image quality.
Beam tilt stability
Number of micrographs taken per day

Zero Fringe System

In addition to the ordinary beam illumination, the CRYO ARM™ 300 II has a unique "Koehler mode" illumination. This mode has no interference fringes and eliminates electron-beam damage to areas not used for imaging and allows you to get more images from a smaller area.
Zero Fringe System

High precision stage drive

The CRYO ARM™ 300 II has a rotation free stage. The advantage of this stage is excellent positional reproducibility. Even if you move samples back and forth between the microscope column and sample storage, you can reuse low magnification images, which we call "global map". It allows for obtaining good sample conditions to capture high-quality data because exposure to the electron beam is greatly reduced.
High precision stage drive


The CRYO ARM™ 300 II is equipped with new version of "JADAS<sup>*</sup>" software to enable novice users to acquire data. New JADAS allows the users to automatically acquire image data by simply selecting the acquisition parameters with a wizard.
* JEOL Automated Data Acquisition System

Contamination free sample storage and removal

The grids can be kept clean in storage for weeks or longer in the CRYO ARM™ 300 II. Moreover, those grids can be replaced from a single grid by the transfer magazine. Liquid nitrogen temperatures and nitrogen gas atmosphere are kept at specimens ejection.
Contamination free sample storage and removal

New Cold Field Emission Electron Gun

The CRYO ARM™ 300 II is equipped with the new cold field emission electron gun (CFEG). This new gun not only has a low energy spread, but also provides an improved probe current stability, allowing users to obtain high quality images at any time.
Stabilized probe current for extended periods of time
<1/2 energy spread compared to Schottky

New Omega filter

The CRYO ARM™ 300 II is equipped with a new improved in-column energy filter, the Omega filter, which is self-adjusting and always delivers the best performance with high stability.
New Omega filter


Main instrument

Electron gun Cold field emission gun (New CFEG)
Standard accelerating voltage 300 kV, 200 kV
Energy filter In-column Omega energy filter (New Omega Filter)
Accessory Hole-free phase plate

Specimen stage / Automated specimen exchange system / Specimen storage

Specimen stage
 Coolant Liquid nitrogen, Automated liquid-nitrogen filling system built-in
 Specimen cooling temperature 100 K or less
 Temperature measurement Near specimen, Cryo-shield, Near LN2 tank
Specimen movements
 X, Y Motor drive (Movements: ± 1 mm)
Piezoelectric elements
 Z Motor drive (Movements: ± 0.2 mm)
 Tilt-X Motor drive ( Tilt: ± 70°)
Rotation Settable to 0°or 90° within the specimen plane
Specimen exchange system Air-lock, Automated cryo-transfer system built-in
 Cooling temperature 105 K or less
 Specimen exchange cartridge Up to 4 specimens can be changed at one time.
Specimen storage Up to 12 specimens can be held
 Coolant Liquid nitrogen, Automated liquid-nitrogen filling system built-in
 Cooling temperature 105 K or less


  • Low accelerating voltage
    (Please make a separate inquiry about requests for the other accelerating voltage except standard.)
  • Bright-field STEM detector
  • Dark-field STEM detector
     (JEOL Automated Data Acquisition System for Cryo-EM)
  • Direct detection camera
  • TEMography
  • Automated tilt series acquisition software for MicroED
  • EDM (Electrostatic Dose Modulator)



GroEL structure at 1.98 Å resolution achieved by only 504 micrographs, a dramatic improvement from 3.1 Å resolution from 1,883 micrographs in a previous study. (as of Oct. 26, 2020 at EMDB)
Data courtesy of Dr. Junso Fujita at Osaka University


Cryo-electron micrograph (left), 3D density map (center) and fitted atomic model (right) of human hemoglobin obtained by high speed data collection, 850 movies per hour.
Specimen courtesy of Dr. Miki Kinoshita at Osaka University

Photosystems I

2.5 Å resolution maps of the photosystem I trimer from Acaryochloris marina viewed from the stromal side perpendicular to the membrane plane (left) and from the side of the membrane plane (right).
Photosystems I
Data courtesy of Dr. Koji Yonekura at RIKEN, Spring-8 Center


Electron diffraction pattern of a thin catalase crystal acquired with Omega filter showing clear diffraction spots visible to ~2.1 Å along the diagonal axis.
Data courtesy of Dr. Koji Yonekura at RIKEN, Spring-8 Center


Cryo-electron tomogram of isolated exosomes with a hole-free phase plate. The tomogram was obtained from micrographs of -60° to +60° tilt range at 2° steps.
Specimen courtesy of Dr. Naoomi Tominaga at National Cancer Center Research Institute and The University of Tokyo.

Application Notes

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