10a-quanta feg 200 abbreviated operating instructions€¦ · quanta feg 200 abbreviated operating...

Prepared by Roger Curtain, Advanced Microscopy facility, January 2013

Quanta FEG 200 abbreviated Operating Instructions

1: Venting the chamber

Select the startup tab on the right hand side of the interface and click the vent button.

The following dialog box is presented; click yes to vent the chamber or no to abort the procedure.

The vent button will be depressed and yellow and an automatic sequence is followed.

The Vacuum status can be observed as the venting procedure is carried out. The high tension will

turn off if it has been on and the column isolation valve V7 will close and all pumps except IGP’s will

stop. The vacuum status panel will transit from green (system pumped) to yellow and then red

(chamber vented) as the nitrogen is introduced.

When the Vacuum Status panel is red open the door slowly. If the vacuum status is grey a serious

error has occurred and an EM unit staff member must be contacted. You cannot fix this error

yourself.

2: Loading a sample

Samples are normally loaded on aluminium stubs these are placed on the round seven sample stage

holder by using the circular tweezers which are used to grip the groove in the stub. Press the stub

firmly down into the hole. If you place samples directly onto the holder please tape them down with

double sided carbon tape as samples can fall off, this especially applies to glass slides cover slips etc.

If the holder is loose tighten the locking nut under the holder, if you do not understand how

mechanical things work ask for help. Before you close the door the samples must be checked by the


height gauge which is the three legged metal object with a nose. The gauge is placed on the XY part

of the sled and all your samples must be below the 10mm mark on the gauge (below the nose). Do

not touch the middle piston with gauge as this generates a touch alarm.

If you see this message in any other context then stop as you sample is touching the pole piece or

BSE detector.

In video mode use the centre mouse button pressed down in the video camera display quad 4 (it

must be unfrozen) and wipe the mouse towards the bottom of the screen, a yellow bar will be

drawn on the display and the further you move the yellow pointer the faster the stage Z will move

down.

Closing the stage door should be done gently a final small resistance is felt, if you encounter a large

one stop. The ALTO stage is packed away at the back of the chamber and there is really not enough

clearance available and the back of the stage touches the alto plumbing.

3. Pump down the chamber


Before pressing the pump button you should select the vacuum mode required. Note unless the

GSED detector is physically plugged in and placed on the pole piece selecting ESEM is really the same

as low vacuum.

Pump down is an automatic sequence the status goes from red to yellow to green. Initially the

chamber pressure will not read as the vac needs to be in the e‐4 mbar range for the cold cathode

gauge to turn on. Note in high vac mode PVP2 (in the room) used in low pressure mode will run for

30 seconds and then stop.

High vacuum will take about 2.5 to 3 minutes to pump down; we have a house rule that even though

the green vac ready light comes on in the status panel do not turn on the HT until the pressure is

below 1e‐4 (in the e‐5 range). If your sample is out gassing or has a huge surface area pumping will

take longer. Large amounts of carbon tape can also slow the pump down time.

If you select low vacuum mode then select the pressure before proceeding 0.5 mBar is typical and

water as the gas. This does not mean you can put wet samples in the chamber. This mode is also

called charge neutralisation mode and is for non‐conductive or poorly conductive samples.

The dialog box below is presented before low vac pumping commences it should normally be set at

No Accessory as show. The solid state backscatter detector is usually fitted. The purpose of this

dialog is to change the range of pressures allowed if one of the other options has been fitted.


4. Turning on the HT and imaging

Once the sample chamber is pumped down to below e‐4 mbar (see house rule above) or has

reached green status in low vac mode you are ready to turn on the high tension HV. First you should

Select the voltage and spot size suitable for your sample type.


Typically 10Kv and a spotsize of 2 to begin with. Also a low magnification of a 100 or so. Click the

HV button it will go yellow indicating HV on status, the valve V7 between the lower column and the

electron gun will open and the High Voltage in the status panel will readout the set voltage. To

obtain an image you need to select a quad (normally 1 the top left) and by clicking in it the databar

should go from grey to blue, make sure the pause icon is not depressed and the large green

Pause Icon in the active quad is not displayed. On the Detector pull down menu (above the green

turtle) select the SE detector. In the case of low vac the SE is disabled and the gaseous and BSE are

the only choices.

In the high vac mode one of the quickest ways to get a suitable setting for the contrast and bright

ness is to click the left most icon the half‐moon for automatic contrast and brightness. Note this

control is not available for the gaseous detector and does not work very effectively for solid state

BSE detector because of the diodes poor frequency response.

5. Focussing an image

On this instrument the only method of focussing is to press the right mouse button down, a double

headed arrow appears. As you move the mouse left to right or right to left the working distance

were the spot is focussed is changed. A move to the left reduces the working distance. Unlike an

optical microscope the sample is not moved. The working distance is only displayed in the databar if

it has been selected to be shown. At low magnification the action of the right mouse sweep causes a

large change to occur and this is progressively reduced as the mag is increased. If you set your

sample height to a 10mm working distance in the video quad then if you focus to a WD of 10 mm

then the sample should be in focus. The F5 function key can be used to toggle between full and quad

mode. It is useful when focussing to use the reduced area mode selectable by the fourth icon or F7.

The green rectangle can be redrawn or moved. The scan is speed up and the focussing will be more

responsive. If you cannot focus go to low magnification the + ‐ keys on the numeric keypad give a 2x

change

6. Setting the Z to the working distance

The microscope has no knowledge of your sample height, the only way to set the Z is to first obtain a

focussed image and then click the couple Z to FWD icon on the toolbar, the red sash is removed and


the Z value in the stage coordinates will be set to the same value as the WD, if this is not the case

then click the update button below the ADD button. It is important to note the Z value is measured

down away from a point in the final lens and the BSE detector is usually fitted, thus less than 10 mm

is available if you set your height to 10mm. If you have samples of different heights then always be

aware of the clearance when setting the smallest sample height. 10mm is the coincidence point of

the X‐ray detector when doing EDS so you should try and maintain your samples close to this height.

7. Moving around the samples

Double clicking a point in your image moves it to the centre cross the cross can be turned on and off

by using the Window menu to the right of tools. In the work pages the Stage Map tab can be used to

move between samples. Important points to note

1: The orientation is that the door is the Y axis the positive to the left hand side and negative X is

closest to the door.

2: The large cross in the stage map is the centre of the stage holder, the small cross is just the

centre of the graphic. The red target is the current position and green is a saved position.

3: Do not click in the white turntable this will rotate your sample and you will become lost.

4: If you double click in the stage map the stage will move in a trapezoid fashion to that point, this

is to correct for backlash in the stage. This is why doing manual moves of the stage is not

recommended.

7. Correcting astigmatism in an image


Once you go beyond a few thousand mag you will not be able to get a sharp image unless the

Astigmatism is corrected. If you hold down the shift key with the right mouse button the pointer

changes to a four headed arrow. Horizontal movement is the X – stigmator and vertical the Y –

stigmator. It is best to use a sample like the gold on carbon “standard” to do this rather than your

sample. You will need an image at least 50000 mag.

You should release the shift key and re‐focus and do the procedure iteratively. The aim is to produce

a circular probe by applying the X and Y correction it is best to do motions separately in X and Y the

aim to separate the lands and not have any directional distortion. While the graphical stigmator

control in the imaging pane in the startup tab can be used (it is the same control) it is best to use the

shift key. The stigmator correction is only valid for the Kv and spot size used it will also differ if a

different changeable aperture is selected.

8. Taking an image

If the camera icon is clicked a single frame will be completed at the camera scan rate this is set in the preference menu available by ctrl+O or at the bottom of many of the menus. The green pause icon will flash slowly in the top left of the image and a short line will progress down the screen. When finished the pause icon is displayed and the beam blanking and pause icons each side of the camera icon while be depressed and active. The camera icon button will be raised again. Select file Save As from the top left menu, always save as tif8 and with the databar selected. The images are saved on the support computer in a shared folder under users. You should create a directory under users with your full name. The Quanta numbers each file with an underscore and three digit number. One trap do not use the characters not allowed in windows filenames; \ / : * ? " < > | The FEI SEM. FIB and TEM interfaces all have this bug they do not trap this and pretend to save your file with no error message all data is lost.


You should select a suitable camera dwell time from the scan pre‐set, select the camera icon into a

new time and click apply and ok buttons. You can type new time and set it if you desire. The frame

time is the amount of time it will take to acquire an image. The longer the time the less noisy your

image will be. Part of the “art” of EM is selecting the right scanning conditions for your job. Ask if

you need a very high quality image for publication as external control of the scanning can be

performed to obtain an 8k x 8k image of 15 bit depth (128mb). The normal image size is 2048 x 1768

Changing the magnification can be done in many ways but selecting the same magnification again is

not easy, thus you are allowed to change the magnification value in the Presets TAB in the

preferences menu. Do not change anything else on this TAB.


At the minimum your image needs to have a scale bar on it. You may need to add or remove items

on the data bar, depending on what you are doing.

If you double click under the scale bar the Edit Label dialog box will appear, if Label is in the list of

Selected: in the Databar list. You can put in a sample descriptor or clear this, it is a standard Edit box

it allows cut, copy and paste. You should use the databar to record the conditions under which you


took the image. It is very easy with modern graphics software to put your lab logo or just blank out

everything but the scalebar if you use the image in a presentation or publish it.

9. Adjusting the Cross Over

On the startup tab if you click the Cross Over button and make it active (yellow) the microscope

lenses are placed in a condition so that you are seeing an image of the filament. The purpose of this

is so the mechanical alignment of the aperture strip can be done.

The instrument is fitted with a changeable aperture strip. To turn grip the large knurled ring

between the thumb and forefinger and twist.


Normally position 6 is used (30 um) but other positions, may be used for EDS typically position 4. The

changer will not come back to exactly the same position. Two lead screws are provided on the

changer to mechanically move it in and out and from side to side. In the crossover mode a green X

will appear on the screen the aim is to centre the white blob of the cross over image over the green

X by using the two screws. Note that the movement is not in the X‐Y direction as the aperture stick is

mounted diagonally. If you are using a bigger aperture size (lower number than 6) then you should

return this to position 6 as the next user might not notice the change and this will apply too much

beam current to the sample. Note the position of the aperture is not readable by the software. If you

are using very large spot sizes 6‐7 then the gun tilt may need to be adjusted to get the beam into the

centre, please right click in the gun tilt to set it to zero when setting back to the standard conditions

of 10kv Spot 2 and Aperture position 6.

Note the aperture changer is quite stiff in action, you should have been shown how to turn this. Grip

the large knurled ring in your hand and twist the stick to the next click stop. Both position 6 and 7

are 30um apertures.


The images above show the two lead screws used to adjust the position of the strip to centre the

spot in cross over mode you should move them slowly. You can use both hands to turn both at once

if you have the skill to do this.

What the image looks like in cross over mode with the cross over image centred over the green

cross. Do not place the beam down a hole but on a sample or stage metal when using cross over and

remember to turn cross over mode off to resume normal imaging.

10. You must do these things

Before you shut the chamber door, check the height of your sample.


Close and open the chamber door gently it is not a refrigerator.

When using high vac mode the pressure must be in the e‐5 range before you turn on the High

Voltage.

If the gold on carbon calibration stub is removed then place it in the brown plastic holder and put

the cap on, do not just discard it in the tray.

Report any errors that come up in the Application Status pop up window, do not clear this.

Return the settings to 10kV spot 2 and aperture on 6, and if you have removed the multi sample

holder please replace it and make sure it is tightened down properly.

Remove your sample and leave the chamber pumped down to high vac when finished. Make sure

the chamber door is closed.

If you have used ESEM mode (trained users only) or removed the BSE detector for another reason,

please replace both LFD and BSE detectors. The notch of the BSE holder goes to the back so that X‐

rays can reach the SDD detector collimator.

You may only place your USB stick into the lead on the desk.

Obey the laboratory rules posted on the entry door.

11. Things you must not do

You may not use a mode or attachments you are not trained to use. And training must be by a staff

member not secondary from another user.

You must not tilt the stage unless you have been given permission, it is better to pre tilt before

closing the chamber. The presence of the ALTO cold stage in the rear of the chamber leaves no

clearance between the stage and the plumbing. If you rip out the plumbing during tilting this will

cause a catastrophic leak into the chamber from atmosphere and may destroy the gun if HT is on.


The image above shows the ALTO stage packed away in the back of the chamber, if anything has

shifted especially the gold cold finger then stop it may jam the stage.

The EDS detector must never be used in ESEM mode; the detector must be in the off state as shown

if the blue LED below the orange/green upper LED is on then you must find out how to turn off the

SDD detector Peltier cooling (This is software controlled by the Oxford EDS control computer)

You must not put liquids or samples containing solvents in the chamber, your sample must be of the

type you submitted in the risk assessment.

You are not allowed to install any software on any of the computers.

10a-quanta feg 200 abbreviated operating instructions€¦ · quanta feg 200 abbreviated operating...

Documents