Recently we have installed a new TEM, JEOL F-200. Last week, we had a serious problem and I would really appreciate some suggestion. While training for sample preparation, someone put a metallic piece. Severe drifting was observed once the observation started and the sample was immediately removed. However once out, the sample was not found in the holder. It probably stayed in inside. We have tried putting other sample thereafter, but the goniometer is not working any further and sample can not be moved (in -ve X, Y, Z, +ve is fine). Stage does not come back to neutral. Therefore, the sample may have got stuck near the pole.
I think the metallic sample got magnetized inside (later I found it does become magnetic in presence of a strong magnet) and came out of the holder due to strong magnetic force.
I donot have prior experience on this problem. Has anyone faced a similar situation? How serious is the problem and what is the way out.
I had similar issue with my specimen. Due to the remanence of pole piece, the only way to remove the lost specimen was to open the microscope. Contact JEOL service and explain your problem.
Thanks Andriy. I have already informed them. In your case, how long did it take to remove it. I have some installations lined up in the TEM, but not sure if I have to reschedule!
I am wondering if switching off the lenses will help. The sample may get demagnetized. And if I vent the column and then evacuate again, it might fly off through the rotary pump. But not sure, if something else happens!
It took less than 20 min for taking out my sample.
The switching off the lenses and the column venting might help, but don't forget the remanence. Just try it! If the goniometer works properly after the lens switching off and venting, then the specimen is out the TEM column.
Unfortunatelly there is no such device for EM as cleaning-tape for old VCR and casette-recorders yet :-) The main solution therefore is: do not put magnetic samples into magnetic field (well, FIB-made lamelas are small enough to be safely put into TEM, though). If you are still putting magnetic samples inside, switch to LM when inserting the sample - this should decrease the magnetic field and lower the chances for sample-uptake (basically switching-off the objective lens). In your case, with gonio not working: are you getting the touch-alarm or just gonio is not responsive? There is a 6V potential on holder, so there is a possibility that the sample is making the contact with the pole-piece, but somehow I don't see the relation regarding the sample in the coloumn and the goniometer not moving... The easies way to remove the sample (but for tehnician, not for you) will be to remove the sample through the gonio-hole in the column. If the particles (or whole sample) has been sucked into the column, then most probably the whole column have to be opened. In each case, you're looking into baking-out the microscope to be able to achieve the vacuum.
Good luck!
PS I'm attaching a few images from older TEM just to clarify how the pole-piece is assambled; you can see the gap (where you suspect your sample is), the upper part of the lens, through-gonio PP image, ...
Dear Ujjal,
you can vent the column, remove goniostage and use the hole to try it by yourself. However, I am 100% sure that you destroy your polepieces. Only a tiny scratch, non-visible by naked eye, is enough to destroy the polepiece. So I absolutely agree with Janez and recommend you to contact your service-man.
Best of luck!
For this procedure the sample must be sufficiently large to be visible for technicians. If the sample has, let say, few microns you probably have to replace objective polepieces assembly by a new one. But I think, this is not your case. According to your description of problem, your "stucked" sample is quite large.
If the microscope is new, don't try to disassemble it yourself. It can be extremely expensive (damages and lost warranty). Call Jeol engineer.
Perhaps, the problem is not so serious. It looks like a mechanical problem with goniometer. Remove the covers from goniometer mechanism and inspect carefully.
Good luck!
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