Python environment setup

With a fresh install of Anaconda 4.2.0 64-bit python=3.5 we can set up a python environment for the new version of ScopeFoundry.

pip install pyqtgraph
conda install pyserial
pip install pydaqmx

Anaconda Python reinstall

Time for a clean up of Python packages.

Uninstalled two different versions of anaconda installed at c:\anaconda and  C:\Users\NIuser\Anaconda2

Before uninstall, `conda list >pkg_list.txt`

These package lists are attached.

Install Anaconda 4.2.0 python 3.5 64bit

Aperture Alignment

Imaging Conditions Au/C sample

• Scan rotation set 180 degrees so image motion matches piezo stage directions, plate handle at image bottom. Up/Down buttons move Up/Down, L/R buttons move R/L (reversed)
• To see Au grains of ~ 30 to 120 nm, need 10 to 50 kX mag (relative to 19/21 inch display)
• Working with 120 um aperture 3 nA mode
• Gun -53.0 -65.0
• App +54.1 +79.5
• Stig -23.7 +13.7
• WD 9.098
• Apparent Image Shift with increasing WD
• if Ax becomes more positive, shift direction becomes more left
• if Ay becomes more positive, shift direction becomes more vertical
• Wobble method:
• set wobble amplitude to 5%
• adjust Ax and Ay to minimize wobble
• problem, as you go through best value, phase reverses, hard to catch
• Manual Focus method:
• put manual cross hairs on a feature
• increase WD, see which direction feature moves
• if it moves right, increase Ax
• if it moves down, increase Ay
• if you change aperture position significantly, you will need to re-adjust WD and Stig to recover a sharp image
• once you have the best value, Au/C should look good, you can check with wobble method

Aperture 6, 120 um 3 nA

• Gun -53.0 +65.0
• Aperture +54.1 +79.5
• Stig -23.7 +13.7
• Stig Bal X upper 84.8 lower 100.0
• Stig Bal Y upper 71.3 lower 99.2

Changing to other current/condenser settings mainly changes WD

• For 3.0 nA, WD 9.098 stig -23.4 +15.2
• For 2.5 nA, WD 9.032
• For 2.0 nA, WD 8.986  stig -21.2 +15.8
• For 1.5 nA, WD 8.950  stig -19.5 +17.9  

Defocus of 10 nm is significant (should be less for smaller apertures)

Stig change of 1% is significant

Aperture 1, 60 um (on axis)

• Gun -2.5 -54.5
• App +0.5 +70.3
• Stig +2.0 +27.0
• Stig Bal X upper 84.1 lower 100.0
• Stig Bal Y upper 70.2 lower 99.8
• WD 200 pA 8.915

Other current settings

• Max WD  9.012  stig +14.2 +40.9
• 200 pA WD 8.915  stig +2.0 +27.0
• 100 pA WD 8.905 stig +1.9 +29.3

Aperture 5 90 um

• Gun +10.1 -6.7
• App -14.5 +20.6
• Stig +2.0 +5.7
• Stig Bal X upper 85.8 lower 100.0
• Stig Bal Y upper 69.7 lower 99.1
• WD 1 nA 8.954
• WD 800 pA 8.938 stig +2.2 +6.9

Aperture 3 30 um

• Gun =45.5 -45.2
• App -51.9 +57.2
• Stig +14.7 +2.5
• Stig Bal X upper 86.7 lower 100.0
• Stig Bal Y upper 71.7 lower 100
• 80 pA WD 8.941 stig +14.7 +2.5
• 60 pA WD 8.929 +15.0 +3.1
• 40 pA WD 8.922 +15. +6.0

 Apps 2 and 4, 20 um and 75 um cannot be aligned properly, out of range with current filament

Auger alignment March 2013

data files in calibration/130318 auger align

Cu auger spectra distorted below 300 eV, all apertures open, 3 kV max @ 23 nA.

Record auger images # 3 2 mm aperture, lowest 3 kV mag. As sample is scanned around (large hole aperture plate) max disk shifts ~ 10% width, major shift if on slope in hole aperture.

• Image 0-2 2 kV CRR 5 gain 0.1
• image 2-3 15 deg tilt instead of 30
• image 4-5 flat, spot gets elongated as now 60 deg takeoff to analyzer
• image 6-7 30 deg tilt 1 kV gain .15
• image 8-9 600 eV
• image 10-11 octo correct 41.8, 46.5
• image 12-13 360 eV no correct gain .2
• image 14-15 octo 42, 46

try auger spectrum spot mode centered at 360 eV maxima with 42, 46 octo, totally distorted

when switching to spot mode counts change dramatically, unstable in time, less than in image mode. Something charging???

Try hard ground instead of SCM, no better.

Go back to reproduce original spectra, even stranger, shut down EIS.

Imaging gave strong hints, reduced area images shifted, depended on scan rates etc. Set sample stage flat, wiggle sample holder etc. Now seems better.

No more jumpy spectra, but still poor low KE performance. Charging or alignment??

SEM Gun/Aperture/Stig Realign - Jan 2017

Mechanical align shown in previous post, here is optical/electrical done at 3 kV

Aperture plate at 3 kV Max settings

Center aperture 60 um #1

1. Used for MAX, 200 and 100 pA
2. Shift gun align onto aperture, must adjust aperture to compensate when emission image vanishes.
3. Gun -2.5, -54.5%, App +2.0, +63.4, tweak gun to maximize current in spot mode image center.
4. On 10 um grid rough focus with aperture align, enough to see grid squares 10 um. 
5. Leave stig zero for now, fix on Au/hopg

Max current align #1 60 um
Green text is wrong, Gun -2.5, -54.5, App +4.0, +61.4, WD 9.24

120 um #6

1. 1.5 to 3 nA settings
2. Gun -53.0, -65.5 App +61.0, +71.5, WD 9.30 
3. To get rough aperture align, do gun align, then find min and max aperture values to illuminate without clipping (one axis at a time) then pick average. 

120 um #6,
(image is mis-labeled, originally confused 120 and 90)

90 um #5

1. 0.6 to 1.0 nA settings
2. Gun +8.6, -6.7 App -8.3, +11.9, WD 9.17

90 um

75 um #4

1. 400 pA setting only
2. Gun +31.0, -92.5 Aperture -33.5, +98.0, WD 9.48

75 um

30 um #3

1. 40 to 80 pA
2. Gun 45.5, -45.2 App -49.0, +51.4 WD 9.42

30 um

20 um #2

1. used for 20 pA only
2. Cannot align, out of range

20 um, out of range of gun and aperture alignment

SEM Mechanical Source Condenser Realign Jan 2017

Current status

• More than one year since the last align
• Still original source, 47,244 hours
• Fill 2.330 A, Ext 5.02 kV, Current 263 uA (EHT off)
• EHT on 8 kV, 197 uA 25.7% extraction

Procedure

1. Start with 10 um grid on Si, flat calibration sample
1. note, clean it next time, lots of dust and particles
2. Delete old recipes
3. Set user and service alignments to neutral
4. record "before" emission images, 3 and 8 kV
5. clear shift relative to 11/8/13, relatively uniform illumination but way off center

3 kV after mechanical source align, all electronic corrections off

3 kV max condenser after source align, all electronic corrections off

3 kV, all electronic alignments neutral, condenser off/on

Any attempt to get closer to mechanical center strongly clips beam

Probably time for source replacement, emitter must be off center in grid cap

Condenser Align

1. Instructions say bring center aperture to mechanical center by mechanical source alignment. Not possible. Come as close as possible, 90 um not too far from center
2. Goal is to avoid image shift with condenser.
3. In Aperture Calibration, for each aperture, select "Cal Gun/Aper Align" and zero gun and aperture alignments, click OK. Now changing probe current only changes condenser. Note some controls disabled if Condenser Normal unchecked. Others disabled while in Cal mode.
4. Draw circle around 120 um aperture (only one fully on screen without electronic shift) with cond off, with 20 pA current, and with max current. Condenser at zero, low and high excitation
5. Pretty good at 3 kV. Somewhat off at 8 and 15 kV, but condenser  excitation is less, so should be less critical. 
6. NOTE: at 15 kV condenser is off for 20 pA, while it is on low excitation for 8 or 3 kV.
7. NOTE: do not change voltages in emission mode, toggle  back to normal for change in EHT so condenser settings update.

After 3 kV condenser align, circles for MAX, 20 pA and condensers off

At 8 kV, MAX off-center relative to 20 pA and OFF

At 15 kV, off-center relative to 20 pA/OFF