Hello everyone.
I'm new to operate SEM. I've to operate SEM Hitachi SU3500 with EDS detector. Can anyone give me some tips or tutorial "how to get good image in high magnification"?
Thanks.
I don't know that model, (I have a Hitachi SU8030), but for any SEM the procedures are going to be similar. So your first job is to get the sample preparation right - what samples do you have? and what have you done so far? What information are you trying to obtain from your sample? - it may be that as Grzegorz has said a W-filament may not be good enough...
For higher resolution/magnification work you are going to need to move to shorter working distances - though this will compromise your depth of focus - so pick flat areas of the sample. You will need to select a probe current value that is small so giving you a finer beam and greater resolution. You may be able to adjust the condenser lens as well - check that manual. Small spot size is what you will need - though this will compromise the amount of noise in the image, so pick a suitable scanning speed for image capture to reduce the noise. The accelerating voltage for W-filament will have to be high for best resolution - BUT it will depend on your sample, some samples will become transparent and others will burn. For most inorganics you should be ok at the higher Vacc values.
Gun alignment first. Get a rough focus, then aperture alignment, move up to very high mags. I would go further than Daniel and always go to highest mag that I can usefully see anything with contrast and try and focus that. You must eliminate any trace of stigmatism - it is not possible to obtain high mag images without this, and it is one of the things that beginners find difficult. Then as Daniel says back off the mag to a useful frame. Use a slow scan to capture at high mags as the noise is usually high.
I teach a lot of students how to use the SEMs in our department, and it requires a lot of practise and guidance. Some students get it and are successful, others never get it and really struggle. So the best thing would be to find someone at your institution who knows how to operate it. It is a matter of responding to what the image is showing you and juggling all the parameters that you have to hand. It is very difficult to write a set of instructions to follow as each sample is different and will require a different approach. So I am afraid there is no substitute for experience here.
On the positive side I notice that manual shows there are a lot of Auto functions on that SEM. Page 2-3 section 2.7. You may find that some of these ease your burden - though it will take you one step away from really understanding how to operate a SEM. I would learn the manual way - but then I do use Auto Bright/Contrast ALL the time!!
Good luck.
Hello, I think your SU3500 has standard tungsten filament. It will be hard to obtain good images at magnifications higher than 40 000. Operating parameters should be always selected to the chemistry, topography and type of material (conductive or non-conductive). Please give some more details about your samples.
Without knowing what kind of samples you have, here's some quick general advice:
1. Focus: I was always taught, with any kind of SEM, to perform my focusing at a significantly higher magnification than I will use to take the image, then drop back to the lower magnification for the image. For instance, if I were imaging at 500X I might focus at 1000X and then take my picture at 500X.
2. Check for astigmatism. If you focus 'up' and 'down' in sequence and see features appear to flip their angle, you have astigmatism error. That's easy to fix, and all SEMs have tools to correct it, so look those up for you microscope.
3. Sample prep: Make sure your sample is as clean as you can make it. No finger oils, etc. Also make you've done your best to eliminate charging artifacts. This is more important if you are imaging an insulator. Sputter coat such samples and use carbon tape to mount the samples
Good luck!
Hi,
maybe you can check the manual attached, it is for Hitachi S-3000N, but the alignment procedure should be the same (or at least very similar).
I don't know that model, (I have a Hitachi SU8030), but for any SEM the procedures are going to be similar. So your first job is to get the sample preparation right - what samples do you have? and what have you done so far? What information are you trying to obtain from your sample? - it may be that as Grzegorz has said a W-filament may not be good enough...
For higher resolution/magnification work you are going to need to move to shorter working distances - though this will compromise your depth of focus - so pick flat areas of the sample. You will need to select a probe current value that is small so giving you a finer beam and greater resolution. You may be able to adjust the condenser lens as well - check that manual. Small spot size is what you will need - though this will compromise the amount of noise in the image, so pick a suitable scanning speed for image capture to reduce the noise. The accelerating voltage for W-filament will have to be high for best resolution - BUT it will depend on your sample, some samples will become transparent and others will burn. For most inorganics you should be ok at the higher Vacc values.
Gun alignment first. Get a rough focus, then aperture alignment, move up to very high mags. I would go further than Daniel and always go to highest mag that I can usefully see anything with contrast and try and focus that. You must eliminate any trace of stigmatism - it is not possible to obtain high mag images without this, and it is one of the things that beginners find difficult. Then as Daniel says back off the mag to a useful frame. Use a slow scan to capture at high mags as the noise is usually high.
I teach a lot of students how to use the SEMs in our department, and it requires a lot of practise and guidance. Some students get it and are successful, others never get it and really struggle. So the best thing would be to find someone at your institution who knows how to operate it. It is a matter of responding to what the image is showing you and juggling all the parameters that you have to hand. It is very difficult to write a set of instructions to follow as each sample is different and will require a different approach. So I am afraid there is no substitute for experience here.
On the positive side I notice that manual shows there are a lot of Auto functions on that SEM. Page 2-3 section 2.7. You may find that some of these ease your burden - though it will take you one step away from really understanding how to operate a SEM. I would learn the manual way - but then I do use Auto Bright/Contrast ALL the time!!
Good luck.
Reduce or eliminate spread of secondary electrons also the signal to noise ratio should high by using a metal coat as all metals give more SE than carbon.
Operating parameters should be always selected to the chemistry, topography and type of material (conductive or non-conductive).Moreover sample details are must asIt is very difficult to write a set of instructions to follow as each sample is different and will require a different approach.
- Badges
- Science method