The TEM maintenance started from the condenser aperture on Feb 6. FEI engineer opened the whole TEM column and replaced the old aligning tube with a new one. Meanwhile, he found that the beam deflector had a crack, an aging problem. Besides other parts, FEI shipped a new deflector to UCI last week, but it was for Tecnai TEM instead of for our CM-20 TEM. Because FEI stopped producing CM-20 TEM for many years, no new deflector was found for our TEM. Last week, a used one was finally shipped to our lab. After installing the deflector, pumping the TEM down and conditioning the HT, the electron beam was seen on this Monday. However, the service engineer could not get the TEM up to a good working condition on Monday and Tuesday. Today (Wed), FEI service manager visited us and found that the used deflector did not work properly. He is contacting the related people in FEI to find a solution for us. He is treating this as an emergency, but he does not know when this issue can be solved. He will keep me posted. When I have news about it, I will put it in comments. Sorry for the inconvenience caused by the downtime of this TEM.
CM-20 TEM is down on 2/6/2013 and up on 3/8/2013
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The TEM is fully up now. I have checked major functions of the TEM ( Imaging, SAED, HR imaging and EDS) today. It is working well. I also calibrated all magnifications ( error< 2%) and recorded a few high resolution (0.2 nm) lattice images. Please enjoy using it.
There are some minor issues, but they do not affect normal work. The attached HR image shows the good performance of the TEM. I will ask the engineer to solve these issues in a few weeks ( when some urgent research work is done). Please use condenser aperture 2 instead of 1 (a little contamination). The beam brightness when using aperture 2 should be good enough for most of TEM work. If there is any problem, please let me know.
FEI engineers finally finished their work yesterday afternoon. I was testing the TEM this morning. Will check all calibrations and other functions (diffraction) this afternoon. There could still be some inconvenience to operate the TEM, but users should get good results after I optimize the system. The TEM will be up later this afternoon.
Yesterday afternoon, the TEM was aligned except the nanoprobe mode. FEI engineers will try to improve the nanoprobe mode, change the filament to LaB6 and do the final adjustment today. If everything goes smoothly, the TEM will be fully up tomorrow.
FEI engineer was trying to align the TEM last week. He did mechnical alignment and changed filament with his local service manager, but the system was still not in good condition. I asked the FEI management to have a senior engineer fix the problem as soon as possible. Today, a senior TEM service engineer will be on campus to continue the work. Hopefully, the TEM can be aligned to the good condition soon.
FEI engineer visited us with a used deflection coil. He tested and concluded that the used part is still in a good condition. He spited the TEM column and installed the part. The TEM is being pumped now. This will continue through the weekend. The engineer will be back on Monday.