JEOL 2100 Microscope Parameters

wavelengths

• 200kV: 0.02508 A

objective lenses

• f = 2.8 mm
• Cs = 2.0 mm
• Chromatic aberration = 2.1 mm

Alpha settings

• Alpha changes CM setting
  • alpha 1: D510
  • alpha 2: 9510
  • alpha 3: 7C50
• April 24 2008: determined that CM setting of 9D41 gives paralllel beam at 50K mag (no change in image size with changing z height)
• This is closest to alpha 2, therefore use alpha 2 for most normal use
• At very high mag (400K), use alpha 1 for parallel beam (otherwise see different defocus in different parts of image)
• Can use Free Lens Control (or manual mode in iMDS) to set CM to optimum value if desired
• If CM (alpha) is changed, need to realign beam (voltage center, astigmatism, pivot points)

Aperture Sizes

• Condenser : 200 um, 100 um, 40 um, 10 um
• Objective : 60 um, 40 um, 30 um, 5 um
• Selected Area: 120 um, 50 um, 20 um, 10 um

Shutterbox Information

• Late July 2008 - visit by Matthias Stumpf
• He found that the shutter box blanker was connected incorrectly -- now fixed
• He also found that our box must be opposite to the normal box configuration for the blanking to work

Magnification Calibration: Jeol 2100F

• Magnifications calibrated using 2160 cross grid using method described in SerialEM documentation

• Resolution limit of this microscope is 1.4A

Defocus Offset using iMDS

March 18, 2014

• Focus set at 200,000X
• microscope was at 120keV and first series was taken, then conditioned to 200 keV over 4 hours, let sit ~1 hr, realigned and second series taken, solid carbon grid

• 200kV
• Slope: 1.16
• Offset: 12.17 overfocus

* plot of j2100 df offset at 200 keV:

• 120kV
• Slope: 1.39
• Offset: 16.63 nm underfocus

* plot of j2100 df offset at 120 keV:

May 8, 2014

• Images taken at 50,000X
• Focus set at 200,000X
• experiment done may 8, 2013, 200 kV, solid carbon grid
• Slope: 1.0
• Offset: 26 nm underfocus
• plot of j2100 df offset:
  

-- BillRice - 28 Sep 2007

* 20140318_120-200kVdefocustest.xls: defocus test worksheet