Scanning Electron Microscope

Here is my new toy, an International Scientific Instruments model "Super III A" scanning electron microscope, vintage 1980.

And a slightly different view.

Exactly how, you wonder, did I acquire a scanning electron microscope? To make a long story short, a friend of mine (thanks Ken) at the University of Rochester noticed an advertisement on the Rochester Craig's List: "Scanning Electron Microscope - Free To Good Home". Turns out that the U of R Materials Science Department had pitched this instrument some years back. A grad student in the Mechanical Engineering Department carted it away, set it up in his apartment, took a few micrographs, found that the instrument was not producing a good enough vacuum to get decent resolution (the specs claim 70 Å should be routine) and embarked on an overhaul of the vacuum system. For those of you unfamiliar with the graduate school experience, let me pass on a few words of wisdom from Earl Peters (who was the executive director of Cornell's Chemistry department back when I was in grad school): "When you find yourself with some free time, sit back, relax and try to remember what you're forgetting to do." The overhaul proceeded as far as partial disassembly, years passed, Thesis writing ensued, plans to move on were made, a half ton of microscope parts didn't fit into the plans. The ad was placed, e-mails were exchanged, a generous offer of help with the move was made (thanks Jace), parts and manuals were exhumed from basement nooks and closet crannies, loaded into cars and transported to my Syracuse basement.

Did I mention that the microscope needed some work? To see the gruesome details, follow the links. I decided to start with the most obvious problem, a high vacuum valve that had been damaged in the earlier overhaul attempt. Since the valve is the central piece of the high vacuum system, I figured the best approach would be to pull out the whole system, repair the valve, clean all components, install new seals and reassemble. Another problem centered on the oil filled high voltage power supply that had been unsealed, allowing oil to slosh out and dirt to enter. This was resolved by the straight forward, but tedious, recovery and filtration of the oil, cleaning, refilling and sealing of the case. A less immediate problem is the disintegration of the original vibration isolation mounts for the microscope column. Currently, that part of the instrument is mounted on the rigid shipping mounts. Eventually, I plan to replace the rubber sleeve over coil spring mounts with air springs. Right now, I'll just try to get the 'scope working and worry about ultimate resolution later. Other deficiencies included the lack of a roughing pump (to back the high vacuum diffusion pump) and chiller/circulator (to cool the diffusion pump). I have a POS vacuum pump from e-Bay, which I can use for some initial leak testing, but I will need to get a better pump for operation. If I lived in a warmer climate, I would probably try to find a used, refrigerated, circulating bath to cool the diffusion pump. But, here in sunny Syracuse, the basement is usually ~ 50ºF, so I'll try to make a simple circulator with an air to water heat exchanger.

That was easy (NOT). Only slightly easier was finding a dedicated circuit to plug into (warning, if you are a building inspector, following this link may result in a heart attack, cerebral hemorrhage, or, after drinking enough to get it out of your head, liver failure). Alrighty then, time to fire it up.

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