Texas Tech University

STEM 8100 SOP


Training Videos


SOP

EOX (IMAGING CENTER)

HITACHI H-8100 STEM

 

 

Operating Instructions for the:

 

HITACHI  H-8100

 

200KV ANALYTICAL SCANNING/TRANSMISSION ELECTRON MICROSCOPE (STEM)

 

Revised 08/14

Mary Catherine Hastert


 

 

 

 

 

 

 

 

 

Compiled and Written by

Mark J. Grimson, PhD

HITACHI H-8100 STEM

BASIC ALIGNMENTS AND OPERATIONS

 

 

 

The Hitachi H-8100 TEM is a complex, research grade scanning/transmission electron microscope (STEM) with analytical as well as ultra-high resolution imaging capabilities.  Systematic theoretical instruction combined with practical hands-on training is the best way to thoroughly understand the utility and capabilities of this complex and delicate instrument.  These instructions are meant only as a guide to the basic, daily alignments and operations of the H-8100, i.e. general imaging and diffraction.  It is by no means a comprehensive guide to all operations of the microscope including ultra-high resolution imaging, SEM, EDX, cryo, and the various diffraction techniques. These advanced, specialized techniques will be dealt with on an as-need basis after mastery of the basic operations has been demonstrated.

 

Please make sure that you follow what I have told you and refer to these instructions as needed. There are some 'NOTES' in these instructions; please read and follow them carefully and do not ignore them. As with all of the equipment in the EOX(IMAGING CENTER), ask before you touch, particularly if you do not know the consequence of your action.

 

 

SAFETY AND THE HITACHI H-8100 TEM

  1. The H-8100 is a high voltage instrument.  Only trained persons are permitted to use this instrument. Do not lend your lab access card to anyone. Do not attempt to “fix” a problem yourself. Do not remove any cover from the instrument. Do not touch any electrical wiring.  
  2. The H-8100 is a radiation producing instrument. The instrument is checked for leaks yearly by EHS.The modern electron microscopes do not pose a radiation hazard. Do not remove any covers from the microscope while in operation.
  3. If there is any water on the floor or water suddenly enters the room where the H-8100 is housed, leave the room  IMMEDIATELY.
  4. In case of fire, if it is safe to do so, turn off the beam (turn down the filament pot), turn off the kVs, and turn the scope to evac mode. Leave the area immediately by the evacuation route. If danger is immanent leave the area immediately.
  5. Do not practice distracted imaging.  Turn cell phones to airplane mode.
  6. Emergency shut down electrical switch is located on the wall behind the 8100 TEM.
  7. FOLLOW ALL TRAINING GUIDELINES.  IMPROPER USE OF THE H-8100 TEM MAY CAUSE PERMANENT DAMAGE.  FOLLOW ALL INSTRUCTIONS.   

 

 

PAY ATTENTION TO THE FOLLOWING GUIDELINES

 

    • NEVER TURN ON THE ELECTRICAL SYSTEM ON THE SCOPE IF THE VACUUM SYSTEM INDICATORS ARE NOT IN THE CORRECT MODE, IF THERE IS WATER ON THE FLOOR, OR IF PAST USERS HAVE REPORTED A PROBLEM THAT HAS NOT BEEN RESOLVED.
    • NEVER TURN ON THE kV'S, HIT RESET ON THE SCOPE, OR BE AT A MAGNIFICATION BELOW 4000 WITH THE AMT SIDE MOUNT CAMERA IN THE BEAM PATH. THE CAMERA CAN BE PERMANENTLY DAMAGED BY EXPOSURE TO AN INTENSE BEAM.
    • NEVER OVERSATURATE THE FILAMENT OR RUN THE BIAS HIGHER THAN 15-20 UA ABOVE THE ACCELERATING VOLTAGE
    • THE FILAMENT LIFE CAN BE SIGNIFICANTLY SHORTENED
    • NEVER CHANGE VOLTAGES WITHOUT FIRST TURNING THE BIAS DOWN.
    • INSERT THE SPECIMEN ROD CAREFULLY SO AS NOT TO SUDDENLY LOOSE THE VACUUM.  SUDDEN LOSS OF VACUUM IS HARD ON THE SCOPE.  LOSS OF VACUUM REQUIRES A 20-30 MINUTE RECOVERY TIME.  KNOW HOW TO INSERT THE SPECIMEN ROD BEFORE YOU ATTEMPT TO DO SO.
    • NEVER TAKE THE SPECIMEN ROD OUT OF THE MICROSCOPE ROOM OR CARRY IT AROUND THE ROOM.  ONCE THE SPECIMEN ROD IS REMOVED FROM THE SCOPE, PLACE IT IMMEDIATELY ON THE SPECIMEN ROD HOLDER.  IF THE SPECIMEN ROD IS HIT OR DROPPED, IT COULD BE BENT AND DAMAGED BEYOND REPAIR.
    • IF THE BEAM LOOKS DIFFERENT OR “FUNNY” OR PRESENTS IN A MANNER THAT YOU DO NOT RECOGNIZE, DO NOT ATTEMPT TO FIX IT.  FIND A MANAGER.  DO NOT START TURNING KNOBS.  IF YOU CANNOT FIND THE BEAM, FIND A MANAGER.  DO NOT START SPINNING KNOBS.
  • IF YOU ARE USING “TILT” MODE, BE SURE TO PUT THE TILT BACK TO “0” BEFORE YOU REMOVE THE SPECIMEN ROD.
  • DO NOT ATTEMPT TO FIX ANYTHING YOURSELF.  DO ONLY THE OPERATIONS YOU WERE TRAINED TO PERFORM.

 

 

 

 

PROCEDURE

  • Enter the H-8100 room, turn on the lights (both overhead and safelight if desired)
  • Check the sign in sheet for previous problems with the microscope.  Ensure the problems have been resolved before proceeding.
  • Sign in on the sheet taking the next available line.
  • Check the vacuum status.  The Gun should be Green, the Column should be Green, the Specimen should be Yellow, and the camera should be Green.    If the vacuum status is not as listed.  Find a manager.
  • Check the prerequisites for Beam Generation Listed below.

 

These abbreviated instructions are to be used only by those familiar with the basic alignments and operations of the H-8100.  They are complete in regards to the saturation and alignment procedures, but do not go into detail as to where controls are and what they do.  Therefore, proven proficiency and an understanding of basic alignments and operations (e.g. specimen insertion, brightness control, Dewar filling, TV operation, focus, stigmation, etc.) is a prerequisite to the use of these instructions.

A routine alignment needs to be performed:  1 ) When the microscope is initially turned on; 2) After each user; 3) After each change of kV, and; 4) Periodically during a session if illumination or alignment looks suspect.


1) PREREQUISITES  TO BEAM GENERATION AND ALIGNMENT
(SECTION C.I, page 19)

    • Key Switch (LR): From 'EVAC ON' to 'COL ON'
    • AMT side mount camera and monitor 'ON' Camera out of the beam path
  • Condenser aperture: 1 or 2
  • Objective aperture: OUT ('O')
  • Field limiting aperture: OUT ('O')
  • Specimen holder: OUT (of scope or out of beam path)
    • HV ON (selected kV)
    • Bright/Dark-field selector (MR) set at Bright Field
    • ZOOM mode selected (ML)
    • Filament pot: (OFF (C-C))
    • Magnification: about -5OK (start at 2-4 K to find the beam first)
    • Spot size: Micro 4 (LL control, but shown on monitor)
    • Specimen rod: in the pre-evac position with vacuum toggle to 'EVAC'
    • Tilt: 0°
    • Panel light (MR) ON
    • Data Monitor (UL): adjust brightness
  • Liquid Nitrogen: Fill or top-off (see above)

 

2) TURN ON THE HIGH VOLTAGE
(SECTION C.11, PAGE 19)
Turn on the High Voltage to the desired kV. Do not saturate the filament at this time.

SAFETY: OVERSATURATION OF THE FILAMENT CAN CAUSE FILAMENT DAMAGE.

 

3) COOL THE ANTI-CONTAMINATOR AND COLD-FINGER WITH LIQUID NITROGEN,
(SECTION A.V.B, page 9)
Fill the front and back Dewars if required.

4) INSERT A SAMPLE TO POSITION 'B' (out of beam path)
(SECTION B.1, B.2, pg. 11-12)

Insert an alignment sample to position 'B' in the specimen chamber.  Do not insert the sample into the beam path at this time.

SAFETY:

IMPROPER INSERTION OF THE SAMPLE CAUSES VACUUM LOSS

5) GENERATE THE BEAM (BEAM CURRENT)
(SECTION C.Ill, page 21)
Saturate the filament with a 10-20 µA beam current

6) ALIGN THE GUN (filament halo centering)
(SECTION D.I, page 24)
Check the GUN ALINGMENT and ensure the halo is symmetrical about the central filament image. If the halo is asymmetrical as you saturate and slightly desaturate the filament, use the GUN TILT X, Y controls to make the halo symmetrical. Center the filament image on the screen with the GUN HORIZ X, Y controls.

7) SELECT AND CENTER THE CONDENSER APERTURE
(SECTION D.11, page 25)
Choose and center the saturated filament image. Rock the BRIGHTNESS control through cross­ over. If the beam does not expand symmetrically about its center, align the aperture to the beam with the mechanical CONDENSOR APERTURE X, Y controls.

8) CORRECT THE CONDENSER ASTIGMATISM
(SECTION D.III, page 27)

If the beam is not round (or nearly round) at cross-over, the Cl lens is astigmatic. Make the image round with the COND STIG X, Y controls.

9) ALIGN THE CONDENSER LENS (Cl WITH C2)
(SECTION D.IV, page 28)

Check that C 1 is aligned with C2 by centering the beam on the screen at cross-over and changing the spot size (SPOT SIZE control) from 1-4 (as shown on the CRT). Ifthe beam moves off the center as the spot size is changed, it needs to be corrected. Use the following controls at the respective spot sizes to re-center the barn at both spot sizes. Repeat until little or no movement occurs.

Spot Size 1..............Center with BRIGHTNESS CENTERING X, Y

Spot Size 4..............Center with GUN HORIZ X, Y

10) INSERT THE SAMPLE TO POSITION 'C' (into beam path)
(SECTION B.I.2, page 12)
Insert the sample into the beam path (position 'C').

11) INSERT THE AMT SIDE MOUNT CAMERA INTO THE BEAM PATH
(SECTION B.II, page 14)

INSERT THE AMT CAMERA INTO THE BEAM PATH USING THE TOGGLE SWITCH.  THE BEAM MUST BE SPREAD AND THE MAGNIFICATION ABOVE 4.3K FOR THE SAFETY OF THE CAMERA.

12) SET THE SAMPLE EUCENTRIC HEIGHT
(SECTION B.III, page 15)
Correct the eucentric ('Z') height of the sample.

13) RETRACT THE MODEL AMT CAMERA INTO THE BEAM PATH
(SECTION B.II, page 14)

14) ALIGN THE OBJECTIVE LENS (VOLTAGE CENTERING)
(SECTION D.VI, page 29)

Correct the Objective lens alignment (Voltage Centering). Find and center a prominent feature on the specimen (a hole or piece of junk).  Increase the magnification to about 60kx and focus.

Center the beam PERFECTLY on the viewing screen with the BRIGHTNESS X, Y controls. ALWAYS KEEP THE BEAM CENTERED DURING THIS STEP.

 

Push HV MODUALTION and note the image on the monitor. If the reference point is shifting, use the BEAM TILT X, Y controls to stop the image shift. Tum off the HV MODUALTION.

Go towards cross-over and re-center the beam with the BRIGHTNESS X, Y controlsSpread the beam and push the HV MODULATION Correct the shift with the BEAM TILT X, Y again until there is NO image movement (the image should pulse in and out of the screen) when the beam is exactly centered at cross-over.

Go to 120kX and repeat the above procedure..

 

15) INSERT AND CENTER THE OBJECTIVE APERTURE
(SECTION D.VII, page 30)

Make certain the beam is on a part of the sample that will diffract the beam ( e.g. Formvar film). Set the magnification to around 8.0k.x. Depress the DIFF. button. Turn the DIFFRACTION SPOT control knob to obtain a bright spot (caustic figure) Use the BRIGHTNESS control to sharpen the spot. You should see a bright central spot with concentric rings surrounding it.

Insert the objective aperture of choice.  You should see the image of the objective aperture somewhere on the screen.  If not, adjust the BRIGHTNESS until the edge of the aperture is sharp and in focus.

Using the mechanical OBJECTIVE APERTURE X, Y controls, center the aperture image around the caustic figure.  You may need to adjust the DIFF control and/or the BRIGHTNESS control to clearly see the edges of the aperture.


Depress the ZOOM button once the aperture is centered.  This will return you to normal viewing mode.

16) INSERT THE MODEL AMT CAMERA INTO THE BEAM PATH
(SECTION B.11, page 14)

17) CORRECT THE OBJECTIVE LENS ASTIGMATISM
(SECTION D.VIII, page 31)

Specimen:  Carbon-coated holey grid.  Find a small, preferably round hole. MAGNIFICATION control: 100-150kX.  While looking at the monitor, focus the hole on the focusing screen using the FOCUS controls until a slightly over-focused fringe can be observed at the edge of the hole (the black fringe).

 

Center the beam at cross-over using the BRIGHTNESS and BRIGHTNESS CENTERING X, Y controls. A perfectly centered beam is a requirement for these steps. Spread the beam with the BRIGHTNESS control while watching the fringe on the monitor until a good contrast is achieved.

Depress the STIGMATOR 'RESET' toggle immediately above the stigmator controls (LL). This will reset the stigmator controls to the preset 'O' positions determined by the technician at the time of the initial mechanical alignment.

Carefully adjust the FINE-COARSE FOCUS so the native astigmatism is noticeable (the overfocus fringe should appear only on two, opposite edges of the hole if the focus is correct). Note the position of the fringe.

While watching the fringe on the monitor, the turn the STIGMATOR X or Y controls (LL) (one at a time) to try to even out the fringe width around the entire circumference of the hole. Continue adjusting the stigmator controls while continually readjusting the fine focus. You must always be able to just barely see the overfocus fringe during these procedures. If the fringe disappears, as happens during these procedures, readjust the focus so you can just barely see it overfocus.

The final corrected astigmatism will show the over-focus fringe width to be perfectly even around the circumference of the hole. The final check for this is to go from an over-focus fringe to an under-focus fringe using the FINE-COARSE or the FINE-FINE focus control in one-step increments to observe whether the fringe disappears evenly around the hole at focus. If not, very small adjustments on the STIGMA X, Y controls may be necessary to correct.

Once the stigmation procedure is completed, spread the beam and reduce the magnification.  This completes the alignment procedure.  Remove the holey grid and insert your own specimen.

18) RETRACT THE AMT SIDE-MOUNT CAMERA FROM THE BEAM PATH
(SECTION B.11, PAGE 14)

You have now completed the basic alignment of the H-8100. Remove the alignment sample and replace it with your own. Proceed with your session, but be aware of the alignments keep the beam centered with the BRIGHTNESS X, Y controls.

19) TEM ROUTINE SHUT-DOWN

When you have completed your TEM session, routine shutdown is quite simple. However, it is critical that you do leave the microscope in the appropriate condition since a power outage or water failure could possibly cause problems for the vacuum cycling, specimen holder or apertures.

Also, when the H-8100 is left in its proper shut-down configuration, it makes it easier for the next user to turn and align the instrument.

 

  • Filament pot: (OFF (C-C))
  • AMT SIDE MOUNT CAMERA RETRACTED FROM THE BEAM PATH
  • HV OFF (selected kV) (Push HV button twice)
  • Specimen: removed from specimen holder
  • Specimen holder: OUT (in the pre-evac position with vacuum toggle to 'EVAC' Position A, fig.4)
  • Condenser aperture: 1 or 2
  • Objective aperture: OUT ('O')
  • Field limiting aperature: OUT (O)
  • Spot size: Micro 4 (LL control, but shown on CRT (UL)
  • Bright/Dark-field  selector (MR) set at Bright Field 
  • ZOOM mode selected (ML)
  • Magnification: about ~50K 
  • Goniometer Tilt: 0°
  • Panel light: OFF (MR)
  • Data Monitor (UL): brightness turned down 
  • AMT side-mount mount camera OUT (flag down)

II ROUTINE ALIGNMENT (IN CONJUNCTION WITH A VOLTAGE CHANGE)

When changing voltages on the H-8100, the Objective Lens Alignment (i.e. Voltage Centering) is one of the two major alignments that need to be corrected before doing a routine alignment. The other is Condenser Stigmation. The greater the difference in changed voltages, (75 - 100 kV vs. 75 -200 kV, the greater the misalignment of Voltage Center and Condenser Astigmatism will be.

Therefore, for advanced users, when changing voltages you will need to first:

A) Insert a sample and set the eucentric height;

B) Correct Condenser Astigmatism, and;

C) Correct Voltage Center before proceeding from the beginning with the entire routine alignment. Then, during routine alignment, re-do these alignments as a matter of course.

1) PREREQUISITES TO BEAM GENERATION AND ALIGNMENT
(SECTION C.I, page 19)

A routine alignment needs to be performed:
1) When the microscope is initially turned on;
2) After each user;
3) After each change of kV, and;
4) Periodically during a session if illumination or alignment looks suspect.

 

  • Key Switch (LR): From 'EVAC ON' to 'COL ON'
  • AMT camera and monitor 'ON' (UR)
  • Condenser aperture: I or 2
  • Objective aperture: OUT ('O')
  • Field limiting aperture: OUT ('O')
  • Specimen holder: OUT (of scope or out of beam path)
  • HV ON (selected kV)
  • Bright/Dark-field selector (MR) set at Bright Field
  • ZOOM mode selected (ML)
  • Filament pot: (OFF (C-C))
  • Magnification: about ~50K
  • Spot size: Micro 4 (LL control, but shown on monitor (UL)
  • Specimen rod: in the pre-evac position with vacuum toggle to 'EVAC'
  • Tilt: 0°
  • Panel light (MR) ON
  • Data Monitor (UL): adjust brightness
  • Liquid Nitrogen: Fill or top-off (see below)

2) TURN ON THE HIGH VOLTAGE

Turn on the High Voltage to the desired kV. Do not saturate the filiment at this time.

3) COOL THE ANTI-CONTAMINATOR AND COLD FINGER WITH LIQUID NITROGEN
(SECTION A.V.B.2 Page 9)

Fill the front and back Dewars if required.

4) INSERT A SAMPLE TO POSITION 'B' ( out of beam path)
(SECTION B I ,B.2, pg. 1 1- 12)

Insert an alignment sample to position 'B' in the specimen chamber Do not insert the sample intothe beam path at this time

5) GENERATE THE BEAM (BEAM CURRENT)
(SECTION C.III, page 2 1 )

Saturate the filament with 10-20 μA beam

NOTE: At this point, the beam will probably appear grossly elongated when spread either way from cross-over The first alignment to perform is condenser lens stigmation to make the beam nearly round on either side of cross-over.

6) CORRECT THE CONDENSER ASTIGMATISM
(SECTION D.III, page 27)

If the beam is not round (or nearly round) at cross-over, the Cl lens is astigmatic. Make the image round with the COND STIG X, Y controls.
After the condenser lens astigmatism has been corrected, insert the alignment sample into
the beam path (position 'C').

7) INSERT A SAMPLE TO POSITION 'C' (into beam path)
(SECTION B. 1, B.2, pg. 1 1- 12)

8) INSERT THE MODEL AMT CAMERA INTO THE BEAM PATH
(SECTION B.11, page 14)

Insert the AMT camera into the beam path.

9) SET THE SAMPLE EUCENTRIC HEIGHT
(SECTION B.111, page 15)

Correct the eucentric ('Z') height of the sample using the TV monitor (insert the scintillator into the beam path).

10) OBJECTIVE LENS ALIGNMENT (VOLTAGE CENTERING)
(SECTION D.VI, page 29)

The VOLTAGE CENTER will probably be grossly misaligned at this point. It is incredibly important that this is done correctly and carefully several times at increasing magnifications (up to at least 120kx).

Correct the Objective lens alignment (Voltage Centering).  Find and center a prominent feature on the specimen (a hole or piece of junk).  Increase the magnification to about 60kx and focus.

Center the beam PERFECTLY on the viewing screen with the BRIGHTNESS X, Y controls. ALWAYS KEEP THE BEAM CENTERED DURING THIS STEP

Push HV MODUALTION and note the image on the monitor. If the reference point is shifting, use the BEAM TILT X, Y controls to stop the image shift. Turn off the HV MODUALTION.

Go towards cross-over and re-center the beam with the BRIGHTNESS X, Y controls.  Spread the beam and push the HV MODULATION. Correct the shift with the BEAM TILT X, Y again until there is NO image movement (the image should pulse in and out of the screen) when the beam is exactly centered at cross-over.

Go to l20kx and repeat the above procedure.

This completes the prerequisites to the routine alignment after a change in voltage. The rest of the steps are the routine alignment procedures.

11) RETRACT THE MODEL AMT SIDE MOUNT CAMERA FROM THE BEAM PATH
(SECTION B.11, page 14)

12) PULL THE SAMPLE OUT TO POSITION 'B',
(SECTION B.1, B.2, pg. 11-12)

13)ALIGN THE GUN (filament halo centering)
(SECTION D.I, page 24)

Check the GUN ALINGMENT and ensure the halo is symmetrical about the central filament image. Ifthe halo is asymmetrical as you saturate and slightly desaturate the filament, use the GUN TILT X, Y controls to make the halo symmetrical. Center the filament image on the screen with the GUN HORIZ X, Y controls

14) SELECT AND CENTER THE CONDENSER APERTURE
(SECTION D.11, page 25)

Choose and center the saturated filament image. Rock the BRIGHTNESS control through cross­ over. Ifthe beam does not expand symmetrically about its center, align the aperture to the beam with the mechanical CONDENSOR APERTURE X, Y controls

15) RE-CHECK AND CORRECT THE CONDENSER ASTIGMATISM
(SECTION D.111, page 27)

If the beam is not round (or nearly round) at cross-over, the Cl lens is astigmatic. Make the image round with the COND STIG X, Y controls

16) ALIGN THE CONDENSER LENS (Cl WITH C2)
(SECTION D.IV, page 28)

Check that C 1 is aligned with C2 by centering the beam on the screen at cross-over and changing the spot size (SPOT SIZE control) from 1-4 (as shown on the CRT). Ifthe beam moves off the center as the spot size is changed, it needs to be corrected. Use the following controls at the respective spot sizes to re-center the barn at both spot sizes. Repeat until little or no movement occurs.

Spot Size 1..............Center with BRIGHTNESS CENTERING X, Y

Spot Size 4..............Center with GUN HORIZ X, Y

17) INSERT A SAMPLE TO POSITION 'C' (into beam path)
(SECTION B.I, B.2, pg. 11-12)

Insert the sample into the beam path (position 'C').

18) INSERT THE MODEL AMT CAMERA INTO THE BEAM PATH
(SECTION B.II, page 14)

Insert the AMT camera into the beam path.

19) SET THE SAMPLE EUCENTRIC HEIGHT
(SECTION B.III, page 15)

Correct the eucentric ('Z') height of the sample.

20) RE-CHECK AND CORRECT THE ALIGNMENT OF THE OBJECTIVE LENS (VOLTAGE CENTERING)(SECTION D.VI, page 29)

Correct the Objective lens alignment (Voltage Centering). Find and center a prominent feature on the specimen (a hole or piece of junk).Increase the magnification to about 60kx and focus.

Center the beam PERFECTLY on the viewing screen with the BRIGHTNESS X, Y controls. ALWAYS KEEP THE BEAM CENTERED DURING THIS STEP.

Push HV MODUALTION and note the image on the monitor If the reference point is shifting, use the BEAM TILT X, Y controls to stop the image shift.  Turn off the HV MODUALTION.

Go towards cross-over and re-center the beam with the BRIGHTNESS X, Y controls. Spread the beam and push the HV MODULATION. Correct the shift with the BEAM TILT X, Y again until there is NO image movement (the image should pulse in and out of the screen) when the beam is exactly centered at cross-over

Go to l 20kx and repeat the above procedure.

21) RETRACT THE AMT CAMERA INTO THE BEAM PATH
(SECTION B.II, page 14)

Retract the AMT camera into the beam path.

22) INSERT AND CENTER THE OBJECTIVE APERTURE
(SECTION D.VII, page 30)

Make certain the beam is on a part of the sample that will diffract the beam ( e.g. Formvar film)Set the magnification to around 8.0kx. Depress the DIFF. buttonTurn the DIFFRACTION SPOT control knob to obtain a bright spot (caustic figure). Use the BRIGHTNESS control to sharpen the spot. You should see a bright central spot with concentric rings surrounding it.

Insert the objective aperture of choice You should see the image of the objective aperture somewhere on the screen.  If not, adjust the BRIGHTNESS until the edge of the aperture is sharp and in focus.

Using the mechanical OBJECTIVE APERTURE X, Y controls, center the aperture image around the caustic figure. You may need to adjust the DIFF control and/or the BRIGHTNESS control to clearly see the edges of the aperture.

Depress the ZOOM button once the aperture is centered This will return you to normal viewing mode.

23) INSERT THE AMT CAMERA INTO THE BEAM PATH
(SECTION B.II, page 14)

Insert the AMT into the beam path.

24) CORRECT THE OBJECTIVE  LENS ASTIGMATISM
(SECTION D.VIII, page 31)

Specimen: Carbon-coated holey grid.  Find a small, preferably round hole MAGNIFICATION control:   100-150kX.  While looking at the monitor, focus the hole on the focusing screen using the FOCUS controls until a slightly over-focused fringe can be observed at the edge of the hole (the black fringe).

 

Center the beam at cross-over using the BRIGHTNESS and BRIGHTNESS CENTERING X, Y controls. A perfectly centered beam is a requirement for these steps. Spread the beam with the BRIGHTNESS control while watching the fringe on the monitor until a good contrast is achieved.

 

Depress the STIGMATOR 'RESET' toggle immediately above the stigmator controls (LL). This will reset the stigmator controls to the preset 'O' positions determined by the technician at the time of the initial mechanical alignment.

 

Carefully adjust the FINE-COARSE FOCUS so the native astigmatism is noticeable (the overfocus fringe should appear only on two, opposite edges of the hole if the focus is correct). Note the position of the fringe.

 

While watching the fringe on the monitor, the turn the STIGMATOR X or Y controls (LL) (one at a time) to try to even out the fringe width around the entire circumference of the hole. Continue adjusting the stigmator controls while continually readjusting the fine focus. You must always be able to just barely see the overfocus fringe during these procedures. If the fringe disappears, as happens during these procedures, readjust the focus so you can just barely see it overfocus.

 

The final corrected astigmatism will show the over-focus fringe width to be perfectly even around the circumference of the holeThe final check for this is to go from an over-focus fringe to an under-focus fringe using the FINE-COARSE or the FINE-FINE focus control in one-step increments to observe whether the fringe disappears evenly around the hole at focus. If not, very small adjustments on the STIGMA X, Y controls may be necessary to correct.

 

Once the stigmation proced ure is completed, spread the beam and reduce the magnification.  This completes the alignment procedure.  Remove the holey grid and insert your own.

 

Once the stigmation procedure is completed, spread the beam and reduce the magnification.  This completes the alignment procedure.  Remove the holey grid and insert your own specimen.

You have now completed the basic alignment of the H-8100. Remove the alignment sample and replace it with your own.  Proceed with your session, but be aware of the alignments keep the beam centered with the BRIGHTNESS X, Y controls.

TEM ROUTINE SHUT-DOWN

When you have completed your TEM session, routine shutdown is quite simple. However, it is critical that you do leave the microscope in the appropriate condition since a power outage or water failure could possibly cause problems for the vacuum cycling, specimen holder or apertures.

Also, when the H-8100 is left in its proper shut-down configuration, it makes it easier for the next user to turn and align the instrument.

 

  • Filament pot: (OFF (C-C))
  • HV OFF (selected kV) (Push HV button twice) 
  • Specimen: removed from specimen holder
  • Specimen holder: OUT (in the pre-evac position with vacuum toggle to 'EVAC' Position A, Fig. 4) 
  • Condenser aperture: 1 or 2
  • Objective apertureOUT (‘0')
  • Field limiting aperture: OUT ('0')
  • Spot size: Micro 4 (LL control, but shown on CRT (UL) 
  • Bright/Dark-field selector (MR) set at Bright Field 
  • ZOOM mode selected (ML)
  • Magnification: about ~50K 
  • Goniometer Tilt: 0°
  • Panel light: OFF (MR)
  • Data Monitor (UL): brightness turned down 
  • Gatan Model 673 scintillator OUT
  • Gatan Model 673 monitor and controller OFF
  • Gatan Model 794 bottom mount camera OUT (LED over 'computer toggle OFF) 
  • Key Switch (LR):  From 'COL' to 'EVAC' (clockwise)

     

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