PNCC offers imaging on both Gatan K3 and TFS Falcon 4i direct electron detectors.
PNCC’s Krios #1 is now exclusively equipped with a TFS Falcon 4i camera with Selectris X energy filter. Should you use K3 or Falcon 4i? The quick answer is that for most projects, both detectors will provide nearly indistinguishable, excellent quality single particle data. You have the option to choose a detector when submitting your data session request. Note: Krios #2 is also equipped with an optional Falcon 4i.
K3 vs Falcon 4i
One key difference from the K3 detector is that movies can be collected in EER format (recommended). EER files can be seamlessly imported into most major processing packages. The Falcon 4i saves movies at the native camera frame rate (320 fps) and the EER format lets you choose the number of fractions to bin into after data collection (i.e., you choose the number of final frames and dose per frame post-acquisition). Upsampling of images in your chosen processing software enables retention of super-resolution information. While files may be larger than K3 files at larger pixel sizes, files tend to be smaller at pixel sizes below 0.7 Å. Movies can still also be saved in mrc format, which would be similar to “hardware binning” on a K3 in SerialEM.
The Falcon 4i is also paired with the TFS EPU acquisition software, instead of the SerialEM software paired with the K3. The interface is quite different from SerialEM, but not hard to learn. Those accustomed to SerialEM may want to stay on the Gatan K3 camera until they become familiar with EPU (please speak to staff for training if needed).
Link to Falcon 4i EER file format reference:
https://www.biorxiv.org/content/10.1101/2020.04.28.066795v1
Basic differences in camera specs are listed below. You can also find associated links to detector data sheets and further resources. Please reach out to your SPOC with any questions you may have regarding detector suitability for your project and we will be happy to assist.
* EER (includes 16k x 16k super-resolution data, all frames accessible
Links for TFS Falcon 4i:
Falcon 4i datasheet (link to file)
Selectris/Selectris X (https://www.thermofisher.com/us/en/home/electron-microscopy/products/accessories-em/selectris.html )
Links for Gatan K3:
K3 datasheet (link to file)
BioContinuum/Biocontinuum HD (https://www.gatan.com/products/biocontinuum-imaging-filter