LEO LEO 912 OMEGA Guida di riferimento
Brief Manual
G 34-655 e
LEO 912
Transmission
Electron Microscope
LEO 912 OMEGA
Table of contents
1 Microscope Operation
1.1 EM system turn-ON 1
Getting the system ready
1.2 Anticontaminator 1
1.3 High-voltage selection 2
1.4 Operation of specimen holder 2
1.4.1 Removing specimen rod 2
1.4.2 Load specimen 2
1.4.3 Lock-in specimen rod 3
1.5 Basic alignment 4
1.5.1 Preparation for basic alignment 4
1.5.2 Calibrate to preset values 4
1.5.3 Alignment of the spectrometer 4
1.5.4 Alignment of TEM- and SPOT-illumination 5
1.5.5 Beam alignment 5
1.5.6 Adjustment of eucentric plane 6
1.5.7 Adjustment of beam incidence 6
1.6 AIS adjustment 7
1.7 Centration of objective lens aperture 8
1.8 Centration of spectrometer aperture 8
1.9 Centration of spectrometer slit aperture 9
1.10 Correction of imaging astigmatism 9
1.11 Low magnifications (LM) 11
1.12 Medium and high magnifications 11
1.13 Focusing the specimen 11
1.14 Photography 12
1.14.1 Loading and removing film 12
1.14.2 Exposure 13
1.15 Turning - OFF 13
Table of contents
I LEO 912 OMEGA
Left panel
Right panel
MAGNIFICATIONENERGY LOSS
SHIFT STIGSHIFT FOCUS
UPUP
IMAGE DIFF
IMAGE SPEC
OVERLD
PMT
RESET VAC
LARGE
IMAGE
SPECTROMETER
SMALL EXPOSURE
YX
DF
MODE
AIS
MODE
MDF
MODE
DISPLAY
DEFOCUS
DSA
M/LM
MODE
PAR GUN GON CAM VAC IMAGE EXIT
E
BEAM
BLANKER
CURRENT
XY
FILAMENT
ON FAIL
TILT SHIFT
AID CALIBRATE
COARSE FINE
STEP OBJECTIVE ILL APERTURE / SPOTSIZE
TEM SPOT
SPOT FOCUS
ON
DEFL STIG
READY ON
HIGH VOLTAGE
ILLUMINATION
FOCUS BRIGHTNESS
PANEL DIM
Description Panels
I LEO 912 OMEGA
Goniometer
Electron gun
Specimen change
Selected area
aperture
Objective aperture
Specimen holder
Spectrometer
Spectrometer
entrance aperture
Binocular
Viewing chamber
Fluorescent screen
Condenser aperture
Spectrometer slit
aperture
Description Column
II LEO 912 OMEGA
1 Microscope Operation
1.1 EM system turn-ON
Getting the system ready
•Turn key switch over VAC to ON.
– The vacuum system is activated for normal operation.
– Rotary pump starts, Turbo pump starts.
– DOS operating system, LEO 912 program and user data are loaded from the
LEO 912 OMEGA hard disk.
– LEO 912 OMEGA START menu is displayed.
– Monitor display: LOADING SYSTEM DATA SET.
If the following message window appears, you may quit and follow the advice later.
•Confirmation with any key on the keyboard.
– The START menu is displayed on the control monitor.
– The host computer is ready by display of the START menu.
•Push softkey START.
– LEO 912 MAIN menu is displayed.
– Instrument readiness is indicated by a green LCD.
1.2 Anticontaminator
Theuseof liquid nitrogenrequires special safetyprecautions for eyesandhands.See
chapter 2 in the extended manual and contact your safety officer.
•Remove lid from dewar.
•Fill in liquid nitrogen.
– Strong gas evaporation
•Refill after 15 min. and close the dewar with lid.
Version 3.20
OFF
VAC ON
!! IT IS TIME TO BACKUP ALL DATA !!
ON A FLOPPY DISKETTE
!! CHECK THE AIR FILTER !!
IN THE POWER SUPPLY
PRESS ANY KEY TO CONTINUE
EM system turn-ON Microscope Operation
LEO 912 OMEGA 1
1.3 High-voltage selection
•Call the GUN menu with softkey GUN.
– The selected high voltage is highlighted.
•Push the corresponding softkey to change the high voltage.
– The new high voltage value is highlighted.
– The objective lens is calibrated for this high voltage value
(indicated by 2 sound signals).
•Return to main menu with softkey RETURN.
1.4 Operation of specimen holder
☞SPECIAL NOTE:
Lock-in/outis only possible if the red LED
display STOP on the goniometer is out. If
not, air will penetrate into specimen and
filament chambers and the ion getter
pump will shut off.
Rule:
No action if LED display STOP is on.
1.4.1 Removing specimen rod
•Retract rod as far as it will go and turn it carefully counter-clockwise until
it stops.
– Airlock valve closes (click).
•Again turn rod counter clockwise until stop and pull it carefully out of the
goniometer.
1.4.2 Load specimen
•Place specimen rod in container.
•Loosen screw with collet chuck and lift it together with holding bow off.
•Insert new grids with tweezer.
•Replace holding bow and tighten screw.
red LED
display
STOP
Microscope Operation High-voltage selection
2 LEO 912 OMEGA
1.4.3 Lock-in specimen rod
SPECIAL NOTE:
The normal position of the specimen rod is in the high vacuum.
Take it only out for specimen exchange.
•Slide specimen rod carefully into goniometer as far as it will go.
•Turn specimen rod carefully clockwise through 90°all the way to
prevacuum position.
– Airlock valve opens (click).
– Red LED STOP is on. Specimen rod pre-pumped in approx. 20 sec.
LED STOP goes out.
•Wait until LED STOP is out.
•Pull specimen rod back to stop and turn it carefully through further 90°;
push rod slowly into the microscopy position
Insertion of specimen rod Preevacuation
Preevacuation concluded Microscopy
Operation of specimen holder Microscope Operation
LEO 912 OMEGA 3
1.5 Basic alignment
☞SPECIAL NOTE:
Use a test specimen (e. g. carbon foil) for the entire alignment of the microscope.
Beam sensitive specimens are not useful for the alignment.
1.5.1 Preparation for basic alignment
•Retract rod as far as it will go and turn it carefully somewhat counter-
clockwise to keep it in this position.
•Insert AIS aperture and activate the AIS mode in the main menu.
•Remove objective aperture.
•Remove spectrometer entrance aperture and slit aperture.
•Turn on high voltage and filament.
– Red LED on top of key FILAMENT is on. Red LED ON is blinking on HIGH
VOLTAGE key.
– Red LED ON on top of key HIGH VOLTAGE is on; High voltage has reached
it´s rated value; Emission current generally > 1µA; if not increase with encoder
CURRENT.
– Fluorescent screen is illuminated; if not move specimen, decrease
magnification,set δE to zero, and adjust brightness.
•Select magnification between 8.000x and 10.000x with buttons
MAGNIFICATION ∆∇
1.5.2 Calibrate to preset values
•Calibrate objective lens current with button CALIBRATE in field FOCUS.
– while the objective lens is calibrated (indicated by 2 sound signals), the
illumination is off.
•Calibrate IM. SHIFT in the menu CAL.
1.5.3 Alignment of the spectrometer
•Reset energy loss to zero with button HCI/0eV in the menu δE.
•Switch to SPEC with button IMAGE/SPEC in the field SPECTROMETER.
– The spectrum caustic is visible on the screen.
•Activate menu PARAMETER, push button CAL and then CALIBR. IM.
SHIFT and CALIBR. ILL. DEFL.
– The illuminating and imaging system are calibrated.
Microscope Operation Basic alignment
4 LEO 912 OMEGA
•Select SHIFT function with button SHIFT/FOCUS in the field
SPECTROMETER.
•Shift tip of the spectrum caustic to the index point of the screen with
the affiliated encoder.
•Correct vertical deviation of the spectrum with the IMAGE SHIFT encoder Y.
•Switch to IMAGE mode with button IMAGE/SPEC.
1.5.4 Alignment of TEM- and SPOT-illumination
•Switch to spot illumination with button ILL Mode and and set spot size to
100 nm with button ILL. APERTURE/SPOT SIZE ∆∇.
•Calibrate C 3 with button CALIBRATE in the field FOCUS.
– Spot should be imaged on the viewing screen.
•Move spot to index point on the small screen with illumination encoders
X, Y in SHIFT/DEFL mode.
•Switch to TEM mode and deactivate AIS mode.
•Center condenser aperture to the index point of the small screen.
•Switch back to spot mode.
•Increase magnification to 31.500x and readjust spot to the center as
described above.
•Increase magnification to 125.000x and readjust spot to the center.
•Switch to TEM with button ILL MODE and center AIS aperture to
the large screen.
1.5.5 Beam alignment
•Select 20.000x with buttons MAGNIFICATION ∆∇.
•Select SPOT mode with button ILL. MODE in the field BRIGHTNESS and
set spot size to 5 nm with buttons SPOT SIZE ∆∇.
•Calibrate objective lens with button CALIBRATE in the field FOCUS.
Focus spot with encoder SPOT FOCUS.
•Move spot to index point with encoders ILL. SHIFT.
•Activate the function BEAM ALIGNM. in the menu GUN.
•Set spot size to 100 nm with buttons SPOT SIZE ∆∇.
Basic alignment Microscope Operation
LEO 912 OMEGA 5
•Shift spot to the index point of the small screen with the encoders X,Y in
the field ILLUMINATION.
•Repeat the beam alignment till the spot positon is identical at 5 nm and
100 nm spot size.
•Push button STORE GUN ALIGNM. and answer PROCEED ? with Y(es).
•Return to main menu with button RETURN and push button ILL. MODE to
select TEM illumination.
– The BEAM ALIGNMENT function is automatically deactivated, when leaving
the GUN menu.
1.5.6 Adjustment of eucentric plane
•Move specimen rod all the way in.
•Activate AIS mode in the main menu.
•Insert an objective aperture and center it (see chapter “Center objective
aperture”).
•Select magnification 25.000x and move specimen detail to the center of the
small screen.
•Calibrate objective lens with button CALIBRATE in the field FOCUS.
•Switch on focus aid with button AID.
– Illuminated ON indicates FOCUS AID is active; specimen detail is moving.
•Focus specimen mechanically using Z-CONTROL buttons, until specimen
detail does not move any more.
– Specimen is now in the eucentric plane of the goniometer.
•Switch off FOCUS AID with button AID.
1.5.7 Adjustment of beam incidence
☞SPECIAL NOTE:
This adjustment step is very important for a single field condenser/objective lens.
Asymmetric diffraction fringes are created by a tilted illumination.
•Deactivate AIS mode in the main menu.
•Select magnification 63.000x.
Microscope Operation Basic alignment
6 LEO 912 OMEGA
Indice
