JEM-2000FX SCANNING TRANSMISSION ELECTRON …...BASIC TEM OPERATION PROCEDURE Panel assignment for Left panels and Right Panels . Transmission Electron Microscopy Laboratories Analytical

Transmission Electron Microscopy Laboratories Analytical Instrument Facility

JEM-2000FX SCANNING TRANSMISSION ELECTRON

MICROSCOPE (S/TEM)

BASIC TEM OPERATION PROCEDURE

Panel assignment for Left panels and Right Panels


Updated on January 24, 2013 2

TABLE OF CONTENTS

Personal and Instrument Safety ..................................................................... 3 Before Staring Your Session .......................................................................... 4

Starting Your Session ..................................................................................... 6

A. Specimen Holder Removal/Insertion ..................................................... 6 B. Electron Emission Setup ........................................................................ 7 C. Beam Alignment .................................................................................... 9 D. Objective Lens Astigmatism ................................................................ 11 Shut Down Procedure .................................................................................. 12 Appendices ................................................................................................... 13 A Variable Condenser Aperture Instructions ....................................... 13 B Specimen and Holder Decontamination Procedure ......................... 14



Personal and Instrument Safety Transmission electron microscopes (TEM) are complex instruments that present dangerous hazards such as high voltage, x-rays, and liquid nitrogen. Misuse of a TEM can cause serious personal injury.

If there is any question about the safe use of the instruments, stop and seek advice from the laboratory staff.

Use the TEM and all instrumentation in the correct manner as described in the available manufacturer’s instrument manuals as well as the user instructions provided in the labs.

§ NEVER attempt to repair or modify the TEM or its peripheral instrumentation, including computer hardware and software anywhere within the Facility.

§ DO NOT use an instrument or perform a task for which you have not received the proper training.

§ DO NOT attempt to use a TEM or any instrumentation when it is being serviced, “tagged” with a problem, or a problem has been logged by a previous user.

§ DO NOT operate a TEM that has not been surveyed and labeled to meet safe X-ray radiation levels by the campus Radiation Safety Office.

• Identify and become familiar with the location of the main electrical disconnect for each instrument.

• Identify and become familiar with your emergency exits and routes.

If any abnormality or problem is encountered during the operation of the TEM, contact the laboratory staff and log the problem in the LOGBOOK.

In case of any abnormal occurrences that may be potentially hazardous to personnel or instrumentation please contact:

§ Lab manager- 919-513-0751 (Dr. Yi Liu) § Department Resource Manager- 919-515-2347 (Roger Russel) § Environmental Health and Safety- 919-515-5445, or 919-515-3000 § Medical emergency – Call 911



Before starting your session, please check: Ø Vacuum gage meter on the Sputtering Ion Pump (SIP) power supply console reads ≤ 5x10-5 Pa (on

the blue scale).

Figure 1 Vacuum gage for SIP.

Ø On L1 panel, ACCEL VOLTAGE READY green light is on, condenser Mini (CM) lens is ON and the

S mode switch is OFF, which corresponds to “L mode” (conventional TEM) (see Figure 2).

Figure 2 Panel L1.

Ø Adjust the brightness of the CRT on panel R1, and go to Page 3. The column valves V2 and V3

displayed on CRT should be open (solid green bowtie) (see Figure 3).

Figure 3 The pump flow chart on Page 3 of the CPU Display on panel R1.



Ø If HT is ON (red button on Panel L1 in Figure 4), check that the BEAM CURRENT displayed value (L1) should be about one-half (+/-3 µA) of the ACCELerating VOLTAGE value displayed on the CRT page 1, e.g. 101 µA for 200kV.

Ø FILAMENT knob (see Figure 4) should be fully counterclockwise to “OFF” position.

Figure 4 Panel L1.

Ø Specimen holder X- & Y- positions display zero on CRT page 2 on panel R1. Ø Goniometer X-tilt is zeroed and is locked (Figure 5)

Figure 5 The goniometer.

Ø Objective lens aperture and field limiting aperture (Figure 6) should be retracted (the lever flipped to

right). Ø Condenser lens aperture lever is positioned to the left with the largest aperture size selected

(Figure 6).

Ø Make sure the viewing screen is covered, then fill the cold trap with liquid nitrogen to full. First user needs to remove the ACD heater first before filling liquid nitrogen.

Locker Goniometer

Z-knob

Function option

Filament knob



Figure 6 Three major retractable apertures.

Staring your session

A. Specimen holder removal/insertion Do not touch the sample holder end without gloves or finger cots. Make sure Filament is OFF before removing or inserting sample holder. Make sure the sample tilt is at Zero position.

Sample Holder Removal is a counterclockwise process:

Ø Pull out the sample holder until it stops; Ø Rotate the sample holder counterclockwise to the end. During rotation, do not apply a

outward force; Ø Slightly pull out the sample holder.

Sample Holder insertion is a clockwise process:

Ø With the pin on the holder matching the notch at 9 o’clock position on the goniometer, push in the sample holder until it stops. DO NOT ROTATE the holder at this stage;

Condenser lens aperture

Objective lens aperture

Field limiting aperture

ACD Heater

Cold Trap



Ø The goniometer red lamp is lit. This begins the vacuum pumping cycle of the goniometer specimen chamber;

Ø When the red lamp is OFF, rotate the specimen holder clockwise until it stops. Because of the negative pressure, it is needed to maintain a pulling force to slowly send the sample holder into the column until it stops. Since at this point the specimen holder is under vacuum, it will be pulled into the column by the vacuum, DON’T LET GO OF THE SPECIMEN HOLDER, until it comes to a complete stop.

CAUTION! The holder may be pulled from your hand by the vacuum and cause severe damage. Grip the holder firmly!

B. Setup the electron emission

1. Accelerating voltage (High Tension)

The default accelerating voltage is set to 181 kV. If the HT button is pressed, the accelerating voltage will ramp up from zero to 181 kV continuously. The high voltage detecting current shown on Panel L1 (Figure 4) is approximately one-half of the accelerating voltage with a 10% difference, e.g. 90±10%µA corresponds to the accelerating voltage 181 kV, and 100±10% µA corresponds to 200 kV. If the HT is OFF, the high voltage detecting current should be zero.

Ø Make sure the ACCEL VOLTAGE value displayed on CRT page-1 is 181 kV. If not, manually set it to 181kV by using ACCEL VOLTAGE toggle switch on Panel L1;

Ø Push HT button, the accelerating voltage will ramp up to 181 kV;

Ø Increase accelerating voltage to 200kV (or lower it to 100 kV for biologists) by using the toggle switch step by step with each step waiting for 2-3 seconds;

Ø Observe the high voltage detecting current (Panel L1 in Figure 4) at each step. The high voltage detecting current should not surge more than 4 µA.

2. Establish electron emission current

The filament used in this TEM is a sharpened Lathanum Hexaboride (LaB6) crystal. With increasing the filament current, emission of electrons will occur. The emission current can be calculated from the reading on BEAM EMISSION subtracted by the high voltage detecting current (before adding the filament current) on Panel L1 (Figure 4). For example, if the high voltage detecting current is 105 µA, and the reading becomes 117 µA after adding the filament current, the total emission current will be 12 µA.

To set-up emission correctly, there are two points to consider: Ø Find the correct filament current, which makes the filament saturated, but not over-

saturated. Over-saturation will shorten the lifetime of the filament. Ø Align the filament with the aid of filament image under desaturation condition.

The saturation position of the filament is pre-set by the Stopper, but it is always good to check if it is over-saturated.

Ø Slowly increase the FILAMENT current knob to position 3 and wait 3 minutes to pre-heat the filament, then very slowly increase to position 4 and wait 1 minutes, followed by a very slow increase to the filament stop. Do Not Push Further to Move Stopper.

Ø If returning the filament knob a little bit, and adjust the BRIGHTNESS knob to make the beam at cross-over position, a shadowed image inside the beam spot will appear, as shown in Figure 7. This is the filament image. It might be necessary to minimize the stigmatism of condenser lens to make it clear (please refer to Beam Alignment section).



Ø Filament alignment can be finished by adjusting the Gun Tilt X & Y on Panel R2 (in the drawer) (see Figure 8) until the brightness reaches the maximum. The filament image should appear symmetrically distributed inside the beam spot, as shown in Figure 7.

Figure 7 Desaturation of the filament LaB6.

Ø Increase the filament current until the filament image almost fully disappears. This is the

position near saturation. The Stopper should be right here, if not, move it to here.

Figure 8 The panel R2.

C. Beam Alignment

Basically, changing spot size should not produce a significant beam shift. Increasing or decreasing magnification should not produce an appreciable movement of the beam. Image should not move during focusing. Image should not move during astigmantism correction. If all these happen, a beam alignment is needed.

Gun Shift

Gun Tilt

Tilt Balance X adjustment

Tilt Balance Y adjustment

Projector Alignment

Intermediate Lens Stigmatism adjustment



1. Condenser lens aperture alignment

a) Select an appropriate aperture size (about the size, see Appendix A). b) Converge the beam to its minimum (cross-over), and center it on the screen using

BEAM SHIFT X and Y (on Panels L1 and R1) (see Figure 10). c) Spread the beam with BRIGHTNESS knob on Panel L1 to ~90% of screen. If it is

found that the beam is off the center of the screen, center it with the aperture knobs (X, Y) (Figure 9).

d) Repeat b) and c) for several times as needed, and follow this procedure whenever aperture size has been changed.

2. Astigmatism correction on condenser lens

a) At the working SPOT SIZE, select MAG1 or MAG2 and a reasonable magnification by SELECTOR (on Panel R1 in Figure 10).

b) Converge the beam to its minimum (crossover) with BRIGHTNESS knob, and center the beam on the screen using BEAM SHIFT X & Y (on Panels L1 and R1) (see Figure 10).

c) Select the function COND STIG button in the “Function Option” on Panel L1 (Figure 10).

d) Adjust the multi-function knobs DEF X on Panel L1 and DEF Y on Panel R1 (Figure 10) to obtain a symmetric and round spot.

Figure 9 Condenser lens aperture (Knob Y1 and Knob Y2 correspond to left and right positions of the level on the CL aperture assembly).

Knob X Knob Y1 Knob Y2

Level



Figure 10 Beam shift knobs and multi-function knobs on panels L1 and R1.

3. Column Alignment a) Gun Alignment: select spot size 1, converge the beam to its minimum (cross-over), if it

is not on the center of the screen, center it with Gun Shift X and Gun Shift Y (Panel R2) (see Figure 8)

b) Condenser lens alignment: switch to spot size 4~6, converge the beam to its minimum (cross-over), if it is not centered, center it with Beam Shift X and Beam Shift Y (panel L1 and R1) (see Figure 10).

c) Repeat a) and b) for several times until the beam at different spot size keep centered.

4. Eucentric height of the sample a) Set magnification at about x5000 by SELECTOR, and bring a recognizable feature of

the specimen to the center of the screen; b) Unlock the X-Tilt driver on the goniometer (Figure 5), and manually tilt the goniometer

10-20 degrees. If the recognizable feature moves away, bring it back by adjusting the Z-knob on the bottom front of the goniometer (Figure 5);

c) Tilt back the stage to zero and focus the sample by FOCUS knob. The focus current should be very close to the table posted on the column. For example, at 200 kV, it should be ~7.01.

5. Tilt Balance Alignment (Tilt Purity) – 1st and 2nd condenser deflectors

This is to adjust the balance between beam shift and beam deflection so that when the Beam Shift X and Y (Figure 10) are adjusted, no Beam Tilt is introduced.

a) Set magnification to about 10 - 40 kX; b) Converge the beam to its minimum (cross-over) by BRIGHTNESS knob, and center

the beam by Beam Shift X & Y (Figure 10); c) Press WOBBLER IMAGE X button (Figure 10), two beams appear on the screen,

adjust IMAGE WOBBLER ADJUST X (Figure 8) on panel R2, so that the two beams combined into one beam;

SELECTOR

Beam Shift X & Y

Multi-function knobs X & Y

Focus

Brightness

Function option

Wobblers

Diff Focus



d) Turn off the WOBBLER IMAGE X button, and turn on WOBBLER IMAGE Y (Figure 10), adjust IMAGE WOBBLER ADJUST Y (Figure 8) to combine the two beams into one beam, and then turn off WOBBLER IMAGE Y.

6. High tension center wobble (varying 1st and 2nd condenser deflectors)

a) Select BRIGHT TILT function on Panel L1 (Figure 4 and Figure 10); b) Under MAG1 mode, set the magnification at 50 kX to 120 kX, depending on what

magnification to be used to image the specimen; c) Select an area containing a recognizable feature (e.g. a sharp corner, or a tip feature),

and bring it to the center of the screen; d) Press WOBBLER HT (Figure 10), the recognizable feature of the sample will move

back and forth around the center black dot on the smaller screen. Try to minimize the shifting by adjusting multifunction knobs BEAM DEF X and Y (Figure 10);

e) Turn off the WOBBLER HT when the recognizable feature is stable on the center and the beam is symmetrically in and out.

7. Intermediate Lens Astigmatism

a) Spread beam with BRIGHTNESS fully clockwise, press DIFF button on panel R1 (see Figure 10).

b) Set camera length to 100 cm using SELECTOR on panel R1 (Figure 10), then adjust DIFF FOCUS (Figure 10) to obtain a small but easily observable caustic image.

c) Adjust the intermediate lens stigmator controls INT STIG X & Y (Figure 8) to obtain a round and symmetrical caustic.

d) Adjust DIFF FOCUS again to obtain a very small and distinctly visible spot.

8. Center the Diffraction pattern – Varies projector lens deflector coils This is important only when you work on diffraction mode. a) Center the incident beam in the diffraction pattern on the screen with projector lens

deflector controls PROJ ALIGN X &Y (Figure 8); b) Return to imaging mode by depressing MAG1.

D. Objective Lens Astigmatism

There are two frequently used methods to fix the stigmatism of Objective Lens.

Ø Select a magnification higher than that which be used for your session.

Method 1 (Fresnel Fringes) - traditional

Ø Use a holey carbon film sample, or find a hole in the sample you are working on. Ø Insert an OBJECTIVE APERTURE and focus the sample. Ø Obtain over-, in- and under-focus conditions using the OBJ-FOCUS control. Ø Observe the Fresnel fringe of the edge of the hole in the under- (bright fringe) and

over-focused (dark fringe) conditions. If the fringe width is not uniform, then objective astigmatism needs correction.

Ø Select OBJ STIG 1 or OBJ STIG 2 and adjust the tmulti-function knobs DEF X & Y to make the Fresnel fringe width uniform along the hole/arc edge.

Ø Turn off the OBJ STIG switch when satisfied.



Method 2 (Live FFT)

Ø Find an amorphous area in the sample, or use carbon film; set a magnification at ~200kX, lift up the screen

Ø Click Start Viewing on DigitalMicrograph software. Ø Under “Process” menu, select ‘LiveàFFT’ option, which will open a continuously

updated FFT of the life image of the specimen. Ø Find and establish 2 to 3 Thon rings by adjusting the Objective Focus. Turn the

objective focus knob counter-clockwise and observe the Thon rings get smaller range not far from the Gaussian focus.

Ø The Thon rings should be close to an oval shape. If not, select OBJ STIG, and adjust the multi-function knobs DEF X & Y to make the ring circular. If the astigmatism is bad you may notice streaking that flips 90 degrees on either side of focus. Start slightly under focus (bright Fresnel fringe at the sample edge) and adjust the objective stigmators to make the FFT Thon rings circular.

Ø Make sure the ring diameters get smaller when the current in the objective lens of the microscope is decreased (typically by turning the objective lens focus knob counterclockwise). If the ring diameters increase, while turning the objective knob counterclockwise, then you are at overfocus range, and need to go to the other side of Gaussian focus (minimum contrast).

Shut Down Procedure Ø Set the image condition at MAG1, 40kX, Spot size 3 L Ø Spread the beam with BRIGHTNESS knob to cover the entire screen Ø Place the protective cover on the viewing chamber window(s) Ø Retract the objective lens aperture and field limiting aperture. Ø Select the largest condenser aperture (lever to the left and largest dot) Ø Retract CCD camera Ø Slowly turn FILAMENT CCW to OFF position (L1) Ø Lower the HT value display on CRT to 181 kV step by step (L1), and then release HT button Ø Tilt goniometer to zero and lock down x-tilt motor drive Ø Center goniometer X-Y stage to zero Ø Make sure EDS detector is fully retracted Ø Turn down CRT screen brightness and panel light controls (R1) Ø Remove specimen holder and specimen; and insert back the sample holder to goniometer Ø Insert ACD heater and depress ACD heat switch (L2) Ø Turn off TV control and TV monitor if used



Appendix A: Variable Condenser Aperture Instructions The variable condenser apertures are selected corresponding to the KNOB 1 and the LEVER position.

Lever Position Left Right

Knobs Active 2 and 3 2 and 4

Knob 1 Position with respect to the DOT ● Relative Aperture Size

Aperture Size (µm) 200 120 70 40 20 NA

• KNOB X and KNOB Y1 are used to move the apertures in the X and Y directions when the

lever is turned to the left.

• KNOB X and KNOB Y2 are used to move the apertures in the X and Y directions when the lever is turned to the right.

CAUTION: To prevent gross misalignment of the condenser aperture assembly; pay very close ATTENTION to the lever position and which of the corresponding KNOBS 2 or 3 that is adjusted.

KNOB Y1

KNOB 1

KNOB X

KNOB Y2

DOT ●

LEVER



Appendix B: Specimen & Holder Decontamination Procedure Liquid Nitrogen should be put into the cold trap of the microscope no less than one-half hour before beginning a TEM session. The following procedure should be followed in the order it is listed:

1. Put sample directly on halogen lamp (on glass) Turn the lamp on a few minutes before use but turn it off while loading the sample so as to be sure not to look directly into the halogen bulb.

2. Put the sample holder (without the sample) into the plasma cleaner for 3 minutes. 3. Put on gloves or finger cots. Bare hands should never touch the sample holder. 4. Clean the tip of the vacuum tweezers (with vacuum turned off) using methanol followed by 1

minute on the halogen lamp. 5. After plasma cleaning the sample holder (while the sample was on the lamp) place the sample

into the holder. 6. Plasma clean for another two minutes (if possible as the plasma cleaner may cause an oxide to

form on the surface of the sample) 7. While loading the sample, do not pump the air lock for too long. In other words, when the

specimen vacuum reaches 50 µA, immediately load the sample. Additional pumping may cause the introduction of hydrocarbons or other contaminates into the system.

Note: Ideally, everything should be done while the sample is hot. If the sample is hot, hydrocarbons introduced to it from the air will be blown off due to the heat.

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JEM-2000FX SCANNING TRANSMISSION ELECTRON …...BASIC TEM OPERATION PROCEDURE Panel assignment for Left panels and Right Panels . Transmission Electron Microscopy Laboratories Analytical