1. MDS Alignment All 3 modes have their own alignment

2. Photo Mode **Press MDS PHOTO button** Set up all imaging conditions: Spot Size (1 or 2) Alpha Angle (2 or 3) Magnification (40-60k) Dose (15-20 e-/Å 2 /sec) After you set up dose, record your C3 lens value so that you can find the correct dose without having to recalculate it

3. How to calculate specimen and image dose and dose rate Example: I o = 15 e/Å 2 /sec M i = 40,000x If M s = 1.25 for screen 1 piAmp/cm 2 = 625 x 10 -12 e/Å 2 /sec I s = 23.4 PiAmp/cm 2

4. Relationship of dose or dose rate between object and detector Object intensity = I 0 = I i M i 2 I i = I 0 / M i 2 I i = I s / M s 2 Screen intensity = I s = I 0 M s 2 / M i 2

6. Dose Calculation (e-/Å 2 /sec) Go to a completely open area (no ice or carbon, just vacuum) Go to 50,000x Magnification *Your dose at 50k in pA/cm 2 is equal to the dose in e-/Å 2 /sec Adjust the following settings to obtain the desired dose for your sample: Size of your beam (using Brightness knob) Spot Size Exposure time

7. MDS Focus **Press MDS FOCUS button** Should be set up the same way as MDS PHOTO Be in MAG 1 Select desired spot size, alpha angle and magnification *generally these settings should all the be same as the settings in PHOTO mode

8. MDS Search **Press MDS SEARCH button** Go to MAG 1 Repeat Voltage Axis Alignment Go to Spot Size of 5 (you may also have to do the spot size alignment at this point if they are misaligned) Spread beam clockwise (using Brightness) until you hear a beep Press SA DIFF Adjust DIFF FOCUS knob until the beam is the desired size

9. Aligning MDS Photo and MDS Search After setting up MDS SEARCH mode, go back to MDS PHOTO Find an area of interest such as ice contamination Center that area in Photo mode using the trackball Press MDS FOCUS Press MDS SEARCH If the area of interest is not in the center than press PLA and use your DEF/STIG X and Y knobs to bring the area to the center Turn off PLA

10. Alignment of Search Mode Photo ModeMisaligned Search Mode: Use PLA & def/stig x y to center area of interest Aligned Search Mode