Project

General

Profile

Actions

Krios-K2 Presets used for 2.8 A proteasome reconstruction in 5 hours data collection at SEMC @ NYSBC

  • Nanoprobe was used to allow smaller beam to be used for multiple targeting on 2 um hole although not essential in this case.

Tecnai Krios 300 kV high tension, XFEG, Gun Lens 4 extraction voltage 4100, 70 um C2 aperture and 100 um objective aperture (except when obtaining grid atlas).
Gatan camera dimension 3710(w)x 3838(h) after rotation to Leginon standard. The size of the beam on the scope main viewing screen always covers the 1.2 um hole at en preset on our scope.
Pixel size is 1.10 A at 22500x scope nominal mag.:

Probe Lens Series Magnification: Preset name: Image Shift (x,y): Dimension: Binning: Camera Dose (e/camera pixel/s): Exposure Time (ms): Specimen Dose Rate (e/A^2): Spot Size: Defocus (m): C2 (um): frame saving: Camera
micro LM 100 gr Aligned 1024x1024 4 n/a 500 n/a 5 0.0 70 no Ceta
micro SA 400** sq Aligned 927x959 4 8 100 n/a 10 -2e-4 70 no K2
nano SA 1300** hl Aligned 927x959 4 8 200 0.004 11 -1.5e-4 70 no K2
nano SA 22500 fc 0,0 924x924 2 >=8* 500 3.3 8 -7e-7 70 no K2
nano SA 22500 fa 0,0 927x959 4 >=8* 250 1.65 8 -1.5e-6 70 no K2
nano SA 22500 en 0,0 3710x3838 1 8 e/pixel/s and ~0.7 um on the specimen 7000 46 8 (-1e-6 to -2e-6) 70 200 ms/frame
**These two magnifications are add-on to standard SA lens series made for NYSBC Krios1. May not be available at other scopes.
  • Note: If the correlation or power spectrum don't work well enough for the standard Camera Dose Rate of 10 e/pixel/s for fc and fa, you may increase it more so not to have to use longer exposure time. The recommended value in literature is meant to give highest DQE at all sampling frequencies. Using a higher camera dose by 50% will certainly not damage the sensor.
  • Note: no defocal pair was acquired in this experiment. Therefore, no ef preset.

Updated by Anchi Cheng over 7 years ago · 5 revisions