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| META TOPICPARENT | name="CryoEM" |
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FEI TF20 Microscope Parameters
wavelengths
* 200kV: 0.02508 A
objective lenses
- f=
- Cs = 2.1 mm
- Chromatic aberration =
Aperture Sizes
- Condensor : 150 um, 70 um, 50 um, 50 um
- Objective : 50 um, 50 um, 50 um, 40 um
- Selected Area: 200 um, 100 um, 70 um, 40 um
CCD information
- Size of camera : 4096 x 4096 pixels
- Pixel size: 15 um
- Post-film mag : 1.76
- Gain in SerialEM : 29 counts / electron
- Gain in EM Menu3: 14.5 counts / electron
CCD : Signal to noise ratio in comparison to film
- SNR of tecnai CCD:
- SNR -tecnai film:
Magnification Calibration: Tecnai F20
- Magnifications calibrated using 2160 cross grid using method described in SerialEM documentation
| Set Magnification (screen up) | CCD Magnification | Unbinned Pixel Size (A) | 2X Binned Pixel Size (A) | Tilt Axis Angle | calibrated film mag |
|---|
| 2100 (LM) | 3,624 | 41.4 | 110 | -80.2 | |
| 1,700 | 2,977 | 50.4 | 100.8 | 90.8 | |
| 2,500 | 4,403 | 34.1 | 68.1 | 90.9 | |
| 3,500 | 6,037 | 24.8 | 49.7 | 91.8 | |
| 5,000 | 8,938 | 16.78 | 33.6 | 91.3 | |
| 6,500 | 11,467 | 13.08 | 26.2 | 91.2 | |
| 7,800 | 13,824 | 10.85 | 21.7 | 91.1 | |
| 9,600 | 17,088 | 8.78 | 17.56 | 91.1 | |
| 11,500 | 20,348 | 7.37 | 14.74 | 91.0 | |
| 14,500 | 25,857 | 5.80 | 11.60 | 90.8 | |
| 19,000 | 33,904 | 4.42 | 8.85 | 91.0 | |
| 25,000 | 42,611 | 3.52 | 7.04 | 90.9 | |
| 29,000 | 50,592 | 2.96 | 5.93 | 90.8 | |
| 50,000 | 88,249 | 1.700 | 3.40 | 92.4 | 51,190 +/- 90 (n=13) | 51,787 +/- 90 at 120kV (n=14) |
| 62,000 | 108,857 | 1.378 | 2.76 | 92.4 | 63,410 +/- 104 (n=12) | 63,735 +/- 160 at 120kV (n=10) |
| 80,000 | 139,813 | 1.073 | 2.15 | 92.4 | 81,190 +/- 111 (n=4) |
| 150,000 | 270,800 | 0.554 | 1.11 | ND | gold lattice |
| 200,000 | 357,100 | 0.420 | 0.840 | ND | gold lattice |
| 240,000 | 427,400 | 0.351 | 0.702 | ND | gold lattice |
| 280,000 | 505,100 | 0.297 | 0.594 | ND | gold lattice |
| 390,000 | 694,400 | 0.216 | 0.432 | ND | gold lattice |
| 490,000 | 862,100 | 0.174 | 0.348 | ND | gold lattice |
| 700,000 | 1.250M | 0.120 | 0.240 | ND | gold lattice |
- Average CCD to film factor: 1.76
- fim mags calibrated using negative-stain TMV, measuring height of layer line at 23A
Magnification Calibration: Tecnai F20 at 120kV
- Magnifications calibrated using 2160 cross grid using method described in SerialEM documentation
| Set Magnification (screen up) | Unbinned Pixel Size (A) |
|---|
| 1,100 | 77.5 |
| 1,500 | 55.6 |
| 1,700 | 48.1 |
| 2,100 | 39.1 |
| 2,500 | 32.5 |
| 3,500 | 23.9 |
| 5,000 | 16.1 |
| 6,500 | 12.4 |
| 7,800 | 10.3 |
| 9,600 | 8.36 |
| 11,500 | 7.15 |
| 14,500 | 5.67 |
| 19,000 | 5.12 |
| 25,000 | 3.45 |
| 29,000 | 2.87 |
Defocus Offset for Low dose mode
- Calculated May 6 2013, df range 500 nm to 3500 nm
- line of best fit: df = 1.12* set_df + 800nm
- Data collected using Focus at 250000X, Exposure at 50000X, spot 4
- Quantifoil carbon grid. Defocus calculated using ctffind3 software
- Plot of df offset data:
* tf20_df2.txt: raw data defocus calcs
- Calculated Nov 29 2013, df range: -500 nm to 3000 nm
- Data collected using Focus at 280,000X, Exposure at 25,000X, spot 5, and Exposure at 50,000X, spot 5, and
- Carbon grid, nickel grid, Borate tubes negatively stained (with uranyl acetate). Defocus calculated using ctffind3 software
- Plots of df offset data:
* x25,000: line of best fit: df = 1.02* set_df + 0.8 um
* x50,000: line of best fit: df = 1.04* set_df + 0.92 um
Defocus Offset for Low dose mode at 120 kV
April 4, 2014 |
