The Bad Astronomer periodically makes posts that show just how cool some astro phenomenon or astro observational capability can be. In keeping with this idea, I find this paper to be just damned impressive. (Apologies for the subscription-only link.) The investigators at Oxford University have one of the best and fanciest transmission electron microscopes (TEM) in the world. In TEM, a highly focused (on the atomic scale!) beam of electrons is fired through a very thin (under 100 nm thick) sample, and the transmitted electrons are analyzed as the beam is scanned over the sample surface. By using very clever electron optics techniques (aberration correction) and the right choice of samples, the investigators have been able to watch the motion of single atoms and few-atom clusters (of praesodymium, which has a big atomic number and therefore interacts strongly with the electron beam) within a carbon nanotube. They can study the formation of 1d crystals this way. Very impressive imaging tool. I want one :-)
7 comments:
How much?
Dan, I think there are only about three of those in the world, all special JEOL models. Perhaps another reader will correct me, but I seem to recall that there's one in Taiwan, one at Cornell, and one at Oxford. I'd guess $3M+.
actually there are quiet a few more. Any FEI Titian model bought with the aberration correction should be able to do similar imaging. In fact the the development system in Berkley achieved 0.5 Angstrom resolution not too long ago. That said one of the keys in this paper is that the image was collected using 80 kV, meaning less beam damage than many other TEM's would induce. I am not sure if a Titan can be operated in that beam energy, but i would think so. And yes most aberration correcting TEM will be around the 3M US mark, give or take a few hundred thousand depending on other configuration options. Also plan on building a facility specifically designed to meet the environmental requirements of the microscope.
Sparrow, thanks for the information! Since there's competition, clearly we can play them off each other and get a massive (say 96%) discount. :-) Of course, if I'm fantasizing about getting one of these, I might as well throw in a dedicated building, salary lines for two fully trained doctoral-level technical staff, and an endowment to cover the annual maintenance contract (which must be $200K or something).
Hi Doug, I just enjoyed being able to contribute. Being an ex-FEI employee I became quite familiar with the product. I am now at an institute considering purchase of one of these instruments in the next few years. One researcher pointed out that at the moment these TEM's are essentially paper factories, especially for the big journals. Hence if you can come up with the right kind of collaborators, the pay off for investing will pay off in the long run. That said staff wise the joy of the newer microscopes is ease of use. So the PhD is required more for the determination of what experiment to run, not how to run it.
... and now the Wolf prize has been awarded to M. Haider, H. Rose and K. Urban for developing abberation corrected electron optics.
As a complete outsider to that field, it seems somewhat astonishing that it took 6 decades from the first electron microscope to get there - seeing that ideas for abberation correction in "classical" optics had been around for a good while.
Would anyone share some insight what the limiting factors in the development were?
In an effort to provide a few points that would illuminate some of the challenges in producing aberration corrected imaging on the TEM I will point out some things to think about. First, from a technical point of view since charged particle optics are not exactly a one to one analogue to light optics I would point out that cromaticity of the beam would be the first order effect. I would say that most development over the last 50 or so years has been addressed to looking at this. If the beam energies are not the same then it is hard to correct the aberrations. Second, I remember a comment from a users group meeting several years ago when these systems were just being launched. The speaker pointed out that 10 years ago his research group had thought that column design had reached a point where the next jump in resolution would be corrective optics. That said the company that he was working with went out of business and set the development of the corrective componets back about 5 years. This is an example of market forces driving development and not technical limitations.
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