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1.9

Centration of spectrometer slit aperture

Switch to SPEC with button IMAGE/SPEC in the field SPECTROMETER.

– Spectrum caustic close to the center of the screen.

Center tip of the caustic to the index point with encoder in the field
SPECTROMETER.

Introduce slit aperture with the aperture drive and adjust the slit width
that the spectrum caustic is within the slit.

– The tip of the caustic should not be too close to the corresponding side of the

slit.

SPECIAL NOTE:
If elastic brightfield is used only, the slit width might be increased so that the caustic
tip is further off the slit edge.

Switch to IMAGE mode with button IMAGE/SPEC.

1.10

Correction of imaging astigmatism

Select a magnification between 125.000x and 250.000x with buttons
MAGNIFICATION

∆ ∇

.

Adjust brightness by changing the emission current with encoder
CURRENT or the illumination aperture angle with the buttons
ILL APERTURE

∆ ∇

.

Note, the illumination angle should not be larger than 1.6 mrad. Larger
illumination angles decrease the image quality.

Through-focus specimen with encoder OBJECTIVE (Grain of a carbon film
or embedding resin).

– The image is astigmatic, if the grain of the carbon film has a privileged direction

in underfocus and is turned by 90

°

in overfocus.

Switch to STIG with button SHIFT/STIG in the field IMAGE.

Compensate astigmatism with the encoders X and Y in the field IMAGE.

– The astigmatism is compensated, if there is no privileged direction of the grain

in under- and overfocus.

Switch back to SHIFT with button SHIFT/STIG in the field IMAGE.

Adjust brightness and magnification to the desired values.

Centration of spectrometer slit aperture

Microscope Operation

LEO 912 OMEGA

9

Summary of Contents for LEO 912 OMEGA

Page 1: ...Brief Manual G 34 655 e LEO 912 Transmission Electron Microscope LEO 912 OMEGA ...

Page 2: ...pectrometer 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 ...

Page 3: ...Y X D F MODE A I S MODE M D F MODE DISPLAY DEFOCUS D S A M LM MODE P A R G U N G O N C A M V A C I M A G E E X I T E BEAM BLANKER CURRENT X Y 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 ...

Page 4: ...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 ...

Page 5: ...e 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 The use of liquid nitrogen requires special safety precautions for eyes and hands See chapter 2 in the extended manual and contact your safety officer Remove lid from dewar Fi...

Page 6: ...r 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...

Page 7: ...ckwise 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 hol...

Page 8: ...urrent generally 1µA if not increase with encoder CURRENT Fluorescent screen is illuminated if not move specimen decrease magnification set δ E 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...

Page 9: ...de 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 00...

Page 10: ...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 ...

Page 11: ...aperture That influences the further procedure Select magnification 3 150x and set illumination angle to 0 5 mrad Center central AIS aperture 37 5 µm 3rd clickstop to the index point Switch to SPOT mode and increase spot size to 100 nm If the brightness is too high increase magnification first Increase magnification to 125 000x keep spot in the center with encoders X Y in SHIFT DEFL mode in the fi...

Page 12: ...the AIS system at 31 500x 16 000x and 8 000x in the same way Check the complete adjustment and optimize it 1 7 Centration of objective lens aperture Select diffraction mode with button IMAGE DIFF in the field IMAGE Adjust the brightness of the diffraction image with the buttons ILL APERTURE Select a camera length of CL 580 mm with the buttons MAGNIFICATION Center the diffraction spot to the index ...

Page 13: ...th buttons MAGNIFICATION Adjust brightness by changing the emission current with encoder CURRENT or the illumination aperture angle with the buttons ILL APERTURE Note the illumination angle should not be larger than 1 6 mrad Larger illumination angles decrease the image quality Through focus specimen with encoder OBJECTIVE Grain of a carbon film or embedding resin The image is astigmatic if the gr...

Page 14: ...erfocus Near focus grain almost disappears Near focus grain remains visible Underfocus Underfocus Astigmatism compensated Astigmatism existent Microscope Operation Correction of imaging astigmatism 10 LEO 912 OMEGA ...

Page 15: ...imen protection 1 12 Medium and high magnifications Insert objective lens aperture if not done yet after finishing LM Insert condenser aperture 400 µm or AIS Select M mode with softkey LM M in the main menu Select magnification between 3 150x and 500 000x with buttons MAGNIFICATION Retract condenser aperture for magnifications below 4 000x Adjust brightness with the buttons ILL APERTURE in the fie...

Page 16: ...ng film There are different types of cassettes available for the different types of fotomaterial Here we deal with sheet film which is loaded in 1 5 mm thick metal cassettes The size of film is 3 25 x 4 inch Load film in the cassettes 1 and put them into the magazine Dry the films in a desiccator for several hours or overnight Ventilate CAM in the VACUUM menu and insert new magazine in the upper p...

Page 17: ...by a sound signal Judgment of the automatic defocus is possible before the photograph is taken Start the exposure with the button EXPOSURE Large screen raises film cassette moves to the exposure position exposure is taken and cassette drops in receiving container Large screen is lowered Camera is ready for the next exposure 1 15 Turning OFF Switch off FILAMENT and HIGH VOLTAGE Return to main menu ...

Page 18: ...86 avenue du 18 juin 1940 F 92500 Rueil Malmaison France Telephone 33 1 41 39 92 10 Fax 33 1 41 39 92 29 E mail 100673 1036 compuserve com LEO Electron Microscopy Inc One Zeiss Drive Thornwood New York 10594 USA Telephone 1 914 747 7700 Fax 1 914 681 7443 E mail 70142 504 compuserve com Plus a worldwide network of dealers Due to a policy of continuous development we reserve the right to change spe...

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