Original Instruction Manual

INSTRUCTION MANUAL FOR MODEL SMS-2-I SUPER I

IT IS IMPERATIVE THAT ALL OPERATORS OF THE SUPER I READ THIS MANUAL CAREFULLY BEFORE OPERATING EQUIPMENT.

International Scientific Instruments, Inc. 1400 Stierlin Road, Bldg A Mountain View, California 94043 (415) 965-8600

Introduction (Page 1)
Control Functions (Page 2)
Start-up Procedure (Page 5)
Specimen Change (Page 7)
Electron Gun Alignment (Page 9)
Operation - Astigmatism Correction (Page 12)
Photography (Page 16)
Shutdown Procedure (Page 18)
Replacement of Electron Gun Cartridge & Anode (Page 19)
Replacement of Objective Aperture and Column Sleeve (Page 21)
Cleaning Anode, Column Sleeves, Slits, Objective Aperture, and Replacement of Filament & Cleaning Electron Gun Cartridge (Page 23)
Procedure for Changing Scintillator (Page 26)
Operation of TV Scan (Page 28)

Trouble Shooting Guide

ISI INTERNATIONAL SCIENTIFIC INSTRUMENTS, INC. 1400 Stierlin Road Mountain View, California 94043

"SUPER I"

1. INTRODUCTION

The SUPER I is a high performance desktop scanning electron microscope. Its fundamental performance is similar to that of the larger SEM's, however, compact design, operational ease and simplicity of installation place it in a category by itself. The SUPER I functions on the following principle: An electron beam emitted from the electron gun is accelerated by a high voltage, focused by a three-stage electro-magnetic lens system and scanned over the specimen surface; the secondary electrons, backscattered electrons, and X-Rays (optional) collected by their respective detectors are converted to video signals; these signals from the surface of the specimen are displayed on the cathode ray tube (CRT) and magnified electronically in synchronization with the scanning beam in the electron optical column.

This manual contains instructions on the operation, service, and trouble shooting of the instrument and is arranged so that an inexperienced operator can understand all aspects with ease. It is imperative that all operators of the SUPER l read this manual carefully before operating the instrument. This will help prevent operational errors and assure the operator in obtaining optimum results from the SUPER I. The experienced microscopist should also read the manual as it will enhance their ability to obtain optimum results as well.

2. CONTROL FUNCTIONS

It is important that this section is studied thoroughly prior to operation of the SUPER I. The following information is intended to familiarize the operator with the control functions of the instrument.

Section	Control	Function
Column	Vacuum valve (rotating)	Cycles vacuum system.
	Column leak valve (pull)	Admits air into column.
	Foreline leak valve (push)	Admits air into foreline.
	Gun alignment (2 sets)	Centers electron beam with respect to the column.
	Stage controls	Moves sample under electron beam.
Display console (right side)	Main power	Applies power to mechanical pump and vacuum electronics.
	Rotary Pump	Applies power to mechanical pump.
	Diffusion pump (DP)	Applies power to diffusion pump heater.
	Operation	Applies power to all electronics.
	Meter Selector	Selects emission current, vacuum or magnification factor on meter.
	Emission	Applies power to electron gun filament.
	Spot size	Changes current in first condenser lens (clockwise decreases brightness of electron beam).
	Working distance (W.D.)	Changes coarse range of objective lens current.
	Focus (fine and coarse)	Changes current through objective lens (focuses electron beam on sample).
	Stigmator (X and Y)	Compensates for astigmatism in electron beam.
	Alignment (X and Y)	Electromagnetically aligns electron beam with respect to column.
	Dynamic focus	Corrects for defocusing a high tilt angles and low magnifications. NOTE: This control should only be used at magnifications of 5,000X and lower.
	High Voltage (KV)	Accelerating voltage selector switch.
Display console (left side)	Image shift (X & Y)	Electronically moves raster on sample.
	Scan mode	Changes vertical and horizontal sweep speeds on and in column.
	Start	Starts single sweep when scan mode is in photo.
	Contrast	Change contrast of image by varying high voltage on PM tube.
	Brightness	Changes brightness of image by varying DC level to CRT.
	Magnification (high/low)	Changes scale on magnification control.
	Magnification	Changes size of area scanned on sample.
	Secondary Electron (SE)	Couples Secondary Electrons to CRT when depressed.
	Backscattered Electrons (BSE)	Couples backscattered Electrons to CRT when depressed.
	External (Ext)	Couples X-Rays to CRT when depressed.
	Spot	Disables scan in CRT and column when depressed.
	Line*	Disables vertical scan in CRT and column when depressed. This mode is also used for positioning the horizontal scan with Y position control for selecting area of interest of X-Ray line profile.
	Position (X and Y)	Positions beam in CRT and column when either spot or line switch is depressed.
	Line Profile	Couples X-Ray rate meter signal to vertical axis of CRT when in line mode.

*This control is used in conjunction with the waveform monitor switch located in the rear of the left bay. When the waveform monitor switch is in the down position and the line switch depressed, the signal is connected to the vertical axis of the CRT. When the signal is displayed in this manner, it can be used conveniently to saturate the filament. Saturation is obtained when maximum amplitude of the waveform is obtained with the emission control. This mode of operation can also be used for aligning the filament. When the waveform switch is in the up position, the signal is removed from the CRT. The switch must also be in the up position when X-Ray information is displayed on the CRT.

3. START-UP PROCEDURE

Before turning the instrument on, check that the controls are in the positions indicated below. Controls and switches not mentioned can be set at any position.

Section	Control	Position
Column	Vacuum valve (rotating)	Position 1
Display console (right side)	Main Power	Off (lower half depressed)
	Diffusion Pump (DP)	Off (lower half depressed)
	Operation	Off (lower half depressed)
	Emission	Full counter-clockwise
	Spot Size	Set at 12:00 to 2:00 o'clock
	Alignment (X and Y)	Set at 12:00 o'clock
	Stigmator (X and Y)	Set at 5.0 on Vernier dials
	Dynamic Focus	Zero
Display Console (left side)	Brightness	Set at 12:00 o'clock
	Contrast	Set at 12:00 o'clock
	Scan Mode	Rapid or Rapid 2
	Magnification	Set at a low magnification
	Secondary Electron (SE)	Depress.

Check that the AC power cable is plugged in properly to a 115VAC receptacle.
Turn on the diffusion pump cooling water. Check to see that the flow rate is approximately 1/2 gallon per minute.
Turn on the main power switch. The red lamp will come on. Next, depress rotary pump switch (RP) momentarily to start the mechanical pump. This is a spring loaded switch and will return to the off position when released. However; the lamp will remain lit. The instrument now has power to the mechanical pump and vacuum circuits, and evacuation of the foreline has begun.

CAUTION - Periodically the input voltage to the instrument should be checked (with main power switch on). This can be done conveniently at the AC receptacle on the back of the display console. The input voltage should be between 98 and 105VAC. If the voltage is not within this range turn off the main power switch and remove power cable from wall receptacle. Remove cover from power transformer and adjust taps on transformer to obtain proper voltage.

Wait about 20 seconds (10 seconds or so after rotary pump evacuation noise ceases). Then turn on diffusion pump and wait 15 minutes for pump to warm up. Turn the vacuum valve control knob clockwise to the 2 position. In this position the rotary pump may again be evacuating air especially if the instrument has not been used for some time. The evacuation sound of the rotary pump should cease in approximately 20 seconds.
When vacuum level reaches 80-100 on the Emission/vacuum meter, turn the vacuum valve control know counter-clockwise to the 3 position.
When the green vacuum indicator lamp comes on the instrument is ready for operation. It is recommended, however, to wait another minute or two.
REMEMBER - THE VACUUM VALVE MUST BE MOVED FROM ONE POSITION TO ANOTHER IN SEQUENCE 1-2-3, 1-2-3, 1-2-3. ALSO, THE COLUMN VENT AND FORELINE VENT VALVES MUST NOT BE USED UNLESS THE MAIN VALVE IS IN THE NUMBER "1" POSITION.

4. SPECIMEN CHANGE

Check that the operation switch is OFF. If not, turn off before proceeding.
Set the Vacuum Valve Control Knob to the 1 position. This is achieved by a clockwise motion from the 3 position.
Pull the Column Leak Valve (refer to fig. 2) towards you for a few seconds. Air will be admitted into the column. In a matter of 1 to 2 seconds the column will be at atmosphere.
Remove the specimen stage by gently pulling out of the specimen chamber. (refer to fig.6)
The standard specimen stage supplied with the SUPER I is a T (tilt) X (horizontal motion) Y (vertical motion) R (rotation). Adaptor plates are provided for 8mm and 15mm working distance. Two specimen holder assemblies are provided, one to accept a 15mm stub and one to accept a 32mm stub. The specimen holder assembly is attached to the specimen stage with 3 screws and is easily interchangeable. When using the 32mm specimen holder assembly the 15mm working distance adaptor plate should be used.
Loosen the specimen holder locking screw and insert a specimen stub (on which a specimen or specimens have been mounted) into the specimen cup. Each specimen should be attached to the specimen stub by methods best suited to the individual specimen. Non-conductive specimens must be coated to prevent charging.
Position the specimen stub so that the top of the specimen is in about the same plane as the top of the specimen cup. Positioning of the sample is not critical, however, since a working distance factor is incorporated in the instrument to determine the correct magnification with respect to changes in the working distance.
Insert the specimen stage into the specimen chamber. Refer to Fig. 2 and 6.
Turn the Vacuum Valve Control Knob clockwise to Valve Position2. When vacuum level reaches 80-100 on meter turn the Vacuum Valve Control Knob counter-clockwise to Valve Position 3. When the green light comes on and the vacuum reading is in the green on the meter the instrument is ready for operation. It is, however, good practice to wait another minute or two.
Translation of the specimen is accomplished with the X and Y stage controls. The X specimen stage control moves the specimen horizontally and the Y control moves the specimen vertically on the CRT. Clockwise movement of the X control moves the image of the sample on the CRT to the right. Clockwise movement of the Y control moves the image of the sample on the CRT up. The rotation control rotates the sample about the sample stub center.
The sample can be tilted under the electron beam from +60° to -30°. Tilting is achieved by rotating the specimen stage in the chamber.

5. ELECTRON GUN ALIGNMENT

Until one is familiar with the instrument, review sections 2 thru 4 before proceeding.
Select desired accelerating voltage and set the Scan Mode Selector to Rapid 1. Also, set Magnification Selector to a low magnification.
Turn the Operation switch on. The lamp in the switch will come on.
Adjust the brightness control so that the CRT Scan is a comfortable level. In the Rapid 1 mode the scanning area is approximately 5cm high and 6cm wide.
Carefully turn the Emission Control clockwise. The emission meter will begin to deflect to the right. Stop turning the emission control at a position where any further movement of the emission control does not give a higher emission meter reading. At this point the filament has been saturated.

Notes:
1. Be careful that the emission control is not turned way beyond saturation. Life of the filament can be greatly shortened or the filament can be burned out.
2. If the emission meter does not deflect when the emission control is turned clockwise the filament is burned out. Replace the electron gun cartridge. Normal operating conditions will give a meter reading somewhere between 100~200µa with a new electron gun cartridge. As the filament ages lower meter readings are to be expected.
Set the Contrast, Spot Size, and Alignment controls as indicated in Section 3. Adjust the 4 alignment screws located on the upper part of the gun chamber. These alignment screws center the electron beam with respect to the electron optical column. While observing the scanning area on the CRT loosen one screw and tighten the opposite screw. Repeat procedure with the two screws located at 90 from the first set that was adjusted. Adjust in this manner carefully until maximum brightness is obtained on the viewing CRT. Maximum brightness should be achieved with both sets of alignment screws.
If during the alignment procedures the image becomes too bright, turn the Spot Size Control clockwise and/or turn the Contrast Control counter-clockwise. Repeat step 5.6 to obtain maximum brightness of the image.
Adjust the Alignment X and Y controls to obtain maximum brightness of the image. If the marks on the X and Y Alignment Controls vary widely from the 12 o'clock position, or if maximum brightness is not achievable, repeat steps 5.6 and 5.7.
Turn the Emission Control a little in the clockwise direction and check if the brightness of the image on the CRT changes. If it does not change return the Emission Control to its original position. If it does change repeat steps 5.6, 5.7, and 5.8.
Set the Scan Mode Selector to normal or Rapid 3. When viewing in Rapid 2 (TV) the intensity of the electron beam must be increased (turn spot size control to approximately the 9 o'clock position), to view the specimen. Refocus if necessary.
Rotate emission control fully counter-clockwise then resaturate while observing the CRT or the photometer. Saturation is achieved when the signal in the CRT and deflection on the photometer does not increase with an increase of the emission control. When saturation is achieved back off on the emission slightly. Once correct alignment has been achieved, an image can be obtained simply by turning on the operation switch and saturating the filament as described in this step.

It may be necessary in some cases, however, to repeat step 5.8.

NOTE: If the column alignment controls are moved it may be necessary to repeat all or part of the alignment procedure.
Normally the emission current should be between 90 - 175 micro amps. If the emission is either higher or lower than mentioned a set of spacers is provided to obtain the proper emission current. When emission is high install one of the thin spacers in the electron gun cartridge between the filament and grid cup. If the emission is to low install a spacer under the anode. The short anode spacer should be tried first. Refer to figure 4. Refer to the following instruction for installing spacers:
1. Disassemble electron gun cartridge as when replacing a filament.
2. Place a this spacer between filament base and grid cup.
3. Reassemble electron gun cartridge as usual.
4. To install anode spacer, remove anode and place spacer between anode and anode chamber.

6. OPERATION-ASTIGMATISM CORRECTION

Check that steps 5.1 through 5.11 have been successfully completed.
Set the Magnification Selector to a low magnification 30X to 100X is recommended for locating the desired area on the specimen stub.
The area of interest on the specimen is located by movement of the X and Y Stage Controls while viewing the image on the CRT at low magnifications. Refer to step 4.10 and 4.11 for stage control instructions. For fast searching it is recommended that the Scan Mode Selector be in the Rapid or Rapid 2 (TV) position while translating the specimen stage. The normal scan mode is used for more detailed viewing of the image.
An image of any area of the specimen surface can be viewed on the CRT by translating the X and Y stage controls. The specimen can also be viewed at any angle between +60° and -30 with respect to the electron beam by changing the tilt of the specimen stage.
The electronic X and Y image shift controls are used to shift the image on the CRT. These controls are normally used to position the image on the CRT at higher magnifications when specimen stage controls become more sensitive. The controls can be left in any position, however, it is recommended that the controls be kept in the mid-position so that when they are needed ample control is available.
When the area of interest is found, set the Scan Mode Selector to the Rapid 1 position and focus by using the Coarse and Fine Focus Controls. Focus is achieved when the image on the CRT is the sharpest. Exact focus is easier to achieve at higher magnification- and then backing off to the desired magnification.
If the image is not sharp or if the image shifts in one direction and then in another direction (almost perpendicular to the former) when focusing, it is necessary to compensate for astigmatism. To compensate for astigmatism, adjust focus until the image on the CRT is between over focus and under focus (between the shift) as mentioned. Then adjust the X and Y Stigmator Controls until the sharpest image is obtained. Refocus and repeat until image is sharp and perpendicular shift is eliminated.
Repeat step 6.7 at a magnification one or two steps higher than the desired magnification required for investigation. Until an operator becomes familiar with the instrument it is recommended that astigmatism is checked, and if necessary compensated, with a known specimen at the start of each day. To obtain optimum results astigmatism should be checked on all specimens where viewing and micrographs are required at magnification of 2 to 3,000X or higher.
If a sharp image cannot be obtained and either X and/or Y Stigmator Control is in the 0 or 10 position, it may be necessary to either change or clean the objective aperture and/or column sleeve. Refer to sections 10 and 11. Also check that the opening of the electron grid cup is not excessively contaminated (Refer to section 9.) and the filament emission is properly saturated (Refer to section 5.). It may also be possible that electronic instability is causing the inability to obtain a sharp image. Refer to the Service and Trouble Shooting Section of the Manual.
Specimens which are charging because of inadequate coating or if the samples are magnetic, repeating of steps 6.7 and 6.8 may be required to obtain a good image. Moving from one area to another on the same sample may also require repeating of step 6.7 and 6.8, especially if the samples are magnetic.
To enhance the image contrast, turn the Contrast Control clockwise. Turning the brightness control counter-clockwise (lowering brightness) may also produce similar results if a bright image is being displayed on the CRT. If the Contrast Control is turned much beyond the 2 o'clock position the image may become excessively noisy. Image contrast can be reduced by turning the Contrast Control counter-clockwise.
To increase the brightness while maintaining the same contrast level rotate the Brightness Control clockwise. Rotating the control counter- clockwise reduces the brightness.
If, in increasing the contrast, as described in step 6.11 a noisy image is encountered, increase the brightness of the electron beam by rotating the Spot Size Control counter-clockwise. Refocusing may be necessary. Turning the Spot Size Control counter-clockwise increases the electron beam size as well as the brightness and if turned beyond the 10 to 11 o'clock position will produce a deterioration in the resolution. This will be noticeable in micrographs at 5,000X and up.
When the image contrast is too high, turn Spot Size Control clockwise and/or turn Contrast Control counter-clockwise until desired contrast level is obtained. The setting of these controls are sample dependent to a certain extent. Anytime the Spot Size Control is changed refocusing and recompensation of the astigmatism may be required. Refer to steps 6.6. thru 6.8. When the Spot Size Control is turned fully clockwise, the electron beam is highly demagnified and the smallest spot size is achieved.
Normally for most work a 200 micron aperture is used. However, if the SUPER I is used routinely from 30X to 3,000X a 100 micron aperture is recommended. The smaller aperture provides greater depth of field at the lower magnifications.
Dynamic focusing is used to compensate for defocusing of the electron beam when working at high tilt angles and low magnifications (below 5,000X). Normally the Dynamic Focus Control is set to correspond with the tilt angle of the specimen stage. If the specimen surface is not parallel with the specimen stub a different setting may be required. When working at magnifications above 5,000X or when using the TV Scan accessory the Dynamic Focus Control should be set to 0°.
Selection of Accelerating Voltage depends primarily on the sample that is being examined. High accelerating voltage is generally used with metallic samples and some metal coated non-metallic samples. A lower accelerating voltage is usually used with metallic samples of a low atomic number and non-metallic samples that have been coated such as biological materials. In some cases samples that are non-conductive or semi-conductive can be examined uncoated using the lowest Accelerating Voltage.

7. PHOTOGRAPHY

Before photographing the image, the operator should be sure that proper focus, astigmatism compensation, selection of desired magnification, and the desired area is being displayed on the CRT. The Polaroid camera should be properly adjusted and loaded with film as described in the Polaroid manual.
4 x 5 Polaroid film, type 52 or PN-55 are normally used. An F stop of 8 to 5.6 is generally used.
Set the Scan Mode Selector to the normal position. Turn the Brightness and Contrast Controls fully counter-clockwise. Increase the Brightness until the scan on the CRT is visible or until a predetermined number (determined during installation) is obtained on the photometer. Then increase the contrast to the predetermined photometer reading. Type 52 and PN-55 film will have separate photometer readings. Turn Scan Mode Selector to Photo. Pull out film cover as per instructions in Polaroid instruction manual and press Photo Start button. The photo scan is approximately 75 seconds. When the photo scan is completed, as observed in the viewing screen, slide the film cover in. Turn handle on film back to P and remove film at a moderate speed, without hesitation and develop for the recommended time. Refer to the Polaroid manual for complete instructions.
The correct use of the photometer provides a usable micrograph every time. There may be times, however, when slight changes in the Photometer setting will be required to obtain exact exposure because of unusual characteristics of the sample being examined. In any case, reproducing the photometer settings will produce good quality micrographs, without wasting film, by an unskilled operator.

8. SHUTDOWN PROCEDURE

Turn off the Operation Switch by depressing the lower half of the switch. The lamp will go out.
Rotate the vacuum valve to the number 1 position and turn off the diffusion pump (DP) switch. Wait for 10 to 15 minutes for the diffusion pump to cool.
Turn off the main power switch. All power should be off including the rotary pump.
Immediately push the rotary pump leak valve (Refer to figure 2) in for a few seconds. This admits air into the foreline.
Turn off diffusion pump cooling water.

NOTE: REMEMBER - THE VACUUM VALVE MUST BE MOVED FROM ONE POSITION TO ANOTHER IN SEQUENCE 1-2-3, 1-2-3-, 1-2-3 -. ALSO, THE COLUMN VENT AND FOELINE VENT VALVES MUST NOT BE USED UNLESS THE MAIN VALVE IS IN THE NUMBER "1" POSITION.

9. REPLACEMENT OF ELECTRON GUN CARTRIDGE AND ANODE

Check that the Operation Switch is Off.
Rotate the Vacuum Valve Control Knob clockwise to position "S" or l.
Admit air into the column by pulling the Column Leak Valve out. Hold valve open until hissing stops.
The SUPER I incorporates a flip top gun. Gently tip the gun till it comes to rest on the stop. Be sure that the discharge bar makes immediate contact with the electron gun cartridge. Refer to fig. 4.
Unplug the electron gun cartridge from its connector. Refer to Fig. 4.

NOTE: When the electron gun cartridge is removed after being in operation it is extremely hot. To avoid being burned remove with a cloth or some other suitable heat resistant material.
Insert a new electron gun cartridge securely into the connector. The cartridge can be plugged in, in either direction.
Lift the discharge bar so that it does not get caught in between the electron gun housing and anode chamber. Tip the gun housing back in place onto the column.
Turn the Vacuum Valve Control knob to the 2 position while applying moderate pressure on the top of the electron gun housing. This will assure a proper seal during the initial pumping. When a reading on the vacuum meter of 80 to 100 is obtained, rotate the Vacuum Valve Control Knob counter-clockwise to the 3 position. When the green light comes on and the vacuum meter is in the green the instrument is ready for operation. It is recommended, however, to wait another minute or two.
When replacing the anode, the above steps are to be followed, except for steps 9.5 and 9.6 which are replaced by the following instructions.

With a set of blunt tweezers grasp the anode by its outer edge and remove. Replace with a clean anode. CAUTION - Never put sharp object in bore of anode.

10. REPLACEMENT OF OBJECTIVE APERTURE AND COLUMN SLEEVE

Check that the Operation Switch is off.
Rotate the Vacuum Control Valve Knob clockwise to position "S" or 1.
Admit air into the column by pulling the Column Leak Valve out. Hold the valve open until hissing stops.
Remove the specimen chamber bolts while carefully holding the specimen chamber in place. After all the bolts are removed lower the specimen chamber approximately one inch and gently pull the chamber forward to disengage the chamber vacuum manifold from the telescoping vacuum manifold. Be careful not to apply excessive tension to the cables attached to the Secondary Electron Detector and Preamp. Place the Specimen Chamber on the table along side the column.
Unscrew the objective aperture holder by turning counter-clockwise. Carefully remove objective aperture holder, the column sleeve will be resting on the holder and will drop out of the column as the holder is lowered. Refer to fig. 6 and 7. To completely remove the sleeve from the column it will have to be taken a part at one joint.
If for some reason the column sleeve does not drop out remove the anode as described in section 9. Then using a clean, blunt object gently apply pressure on the sleeve from the top of the column.
Assemble clean column sleeve and insert into column in reverse order along with clean aperture and aperture holder. Refer to figures 6 and 7.
Carefully insert specimen chamber vacuum manifold into the telescoping vacuum manifold. Raise specimen chamber and seat against bottom of column. Tighten all specimen chamber bolts uniformly.
Turn the Vacuum Valve Control Knob to the 2 position. After a reading of 80 to 100 is obtained on the vacuum meter, rotate the Vacuum Valve Control Knob counter-clockwise to the 3 position. When the green light comes on and the vacuum meter is in the green the instrument is ready for operation. It is recommended however to wait another minute or two.
Recheck specimen chamber bolts to be sure they are secure.

NOTE: REMEMBER - THE VACUUM VALVE MUST BE MOVED FROM ONE POSITION TO ANOTHER IN SEQUENCE 1-2-3, 1-2-3, 1-2-3. ALSO, THE COLUMN VENT AND FORELINE VENT VALVES MUST NOT BE USED UNLESS THE MAIN VALVE IS IN THE NUMBER "1" POSITION.

11. CLEANING ANODE, COLUMN SLEEVES, SLITS, OBJECTIVE APERTURE AND REPLACEMENT OF FILAMENT AND CLEANING ELECTRON GUN CARTRIDGE.

One of the most important requirements to obtain the best results from any electron optical column is cleanliness. Therefore, the SUPER I is no different in this respect. The following procedure is recommended for thorough and effective cleaning of the column parts.

Disassemble the column liner, electron gun cartridge, and objective aperture holder. Save the objective aperture for cleaning using a different procedure.
Clean all parts with a metal polish such as Wenol. This polish is available from all microscope accessory suppliers. Use a cotton swab saturated with metal polish to clean the inside diameter of the sleeves, sleeve joints, etc. The smaller diameters can be cleaned by wrapping a little tissue such as kimwipes around a wooden stick. To clean the outer surfaces saturate tissue or cloth and polish till all contamination is removed. Clean the bores of the splash apertures with polish and a wooden stick shaved down to a small diameter. In the case of the electron gun cartridge and anode where the contamination may be quite heavy a cleaning agent such as Comet, Ajax, etc. can be used with water.
Remove all traces of the cleaning agent and place parts in a beaker of acetone or equivalent solvent in an ultrasonic cleaner for several minutes. As the ultrasonic cleaning action removes the remaining cleaning agent the solvent will discolor. Keep exchanging the solvent until it remains clean then follow up with a final rinse in alcohol and dry the parts thoroughly.
Prior to assembling the parts inspect with a 5X to 10X magnifying lens. A speck of dust or lint in a critical area could defeat the entire cleaning procedure.
Depending on what they are made of, there are several procedures for cleaning apertures. A platinum aperture can be cleaned very effectively by holding in a carbon free flame such as an alcohol burner or propane torch with a pair of platinum tipped tweezers. The aperture should be heated until it is cherry red for 30-60 seconds. To clean molybdenum apertures place in tungsten boat in a vacuum evaporator. Again heat until cherry red for a minute or two or until color of entire aperture is uniform. Turn off heat and let cool before letting air into the system. If air is let into the evaporator before the apertures cool down the apertures will oxidize.

When the column parts are cleaned successfully the stigmator controls should be near the center of the controls when the astigmatism is corrected. Many times when the quality of the image deteriorates one has a tendency to over react and go through the entire cleaning process. Quite often this may not be necessary. If severe astigmatism is encountered and cannot be corrected with the controls generally the problem is dust or lint on the objective aperture or in the objective aperture holder. When the stigmator controls gradually shift towards one end, usually this is an indication of contamination build up. In either case cleaning or replacing the objective aperture and/or cleaning the objective aperture holder may be all that is required. However, when the astigmatism is corrected and the controls are near the center but the quality of the image is poor usually the column liner is the cause and requires cleaning.

To replace filament, remove 2 screws holding electron gun flat ring to electron gun base. Lift off flat ring and grid cap. Clean these parts if necessary as described above. Loosen 4 alignment set screws in base of electron gun cartridge and remove burned out filament.
After cleaning, insert new filament in electron gun cartridge base. Replace grid cap and flat ring. Next replace and tighten (loosely) the two screws holding the flat ring to the electron gun base. Adjust the four alignment set screws so that the tip of the filament is perfectly centered in the hole of the grid cap. Check with 5X to 10X eyepiece. Tighten four alignment set screws and two screws holding down the electron gun flat ring. Re-check alignment. If alignment has moved, re-center. The electron gun cartridge is now ready for use.

CAUTION: DO NOT POUR ANY TYPE OF SOLVENT INTO THE BORE OF THE COLUMN. THE COLUMN BORE DOES NOT REQUIRE CLEANING.

12. PROCEDURE FOR CHANGING SCINTILLATOR

Periodically the scintillator has to be changed to maintain optimum performance of the SUPER I. If bright spots or horizontal lines are observed on the CRT this is an indication that the aluminum coating on the scintillator is deteriorating. When the condenser control has to be positioned past 11 o'clock (in the counter-clockwise direction) to maintain a sufficient noise free signal is an indication that the efficiency of the scintillator plastic is deteriorating. Also, it must be kept in mind that rotating the condenser control counter-clockwise increases the electron beam spot size which will result in a decrease of resolution. When any of the mentioned symptoms occur the scintillator must be changed to regain optimum performance.

The following is the recommended procedure for changing the scintillator:

Vent column as when changing a sample.
Remove sample chamber.
Loosen both small screws that secure preamp to photomultiplier tube cover and gently remove preamp/photomultiplier and set aside.
Unscrew photomultiplier tube cover.
Remove secondary detector from specimen chamber. Hold the detector in position till the last screw is removed to avoid bumping the light pipe against the chamber wall.
Carefully remove collector mesh and unscrew the scintillator retaining ring and set aside.
Remove the scintillator from the light pipe.
Carefully pick up new scintillator by the edge with fine tweezers and place on to light pipe with aluminum facing out (away from light pipe).
Screw retaining ring on to fight pipe. Extreme caution must be taken when handling the scintillator. Finger parts, scratches, and etc. will damage the scintillator. Also, the scintillator can not be cleaned. Wiping the scintillator with a cotton swab, tissue, and etc. will damage the aluminum coating.
Install the secondary electron detector, preamp, and etc. in reverse order.

To check the scintillator high voltage contact, turn on the instrument and leave the emission control in the counter-clockwise position. Adjust brightness to a comfortable level and turn contrast control clockwise. If proper high voltage contact has been made to the scintillator no noise (bright spots on CRT) should appear on the CRT till the contrast control is in the 2-3 o'clock position. Should noise appear before this position is reached with the contrast control indicates a problem in the high voltage contact to the scintillator. If this should occur a small drop of silver conducting paint can be applied at the edge of the scintillator so that the paint makes a connection between the aluminum coating and the retaining ring.

13. OPERATION OF TV SCAN

Turn on instrument and obtain an image on the CRT as described in section 6 of this manual. Be sure Dynamic Focus Control is set to 0°.
Turn the switch on the TV Scan Control box to the on position (the TV Monitor is always on). Rotate the condenser control counter-clockwise to approximately the 9:00 o'clock position. Then adjust to the desired contrast with the contrast control on the Super Mini-SEM display console.
When in the TV Scan mode image brightness is adjusted with the brightness control on the TV Monitor. The contrast control on the monitor is usually left in the full clockwise position, while other controls are used as with any television set. Focusing of the image is achieved in the normal manner. Magnification is changed with the control on the TV Scan Control box.
When switching back to normal scan, the condenser lens control should be returned to the normal position (3:00 o'clock or higher) as well as the contrast control prior to switching the TV Scan off.

CAUTION - Step 13.4 must be performed as described otherwise damage could occur to the CRT tube.

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