Basic Electron Microscopy Arthur Rowe The Knowledge Base at a Simple Level

Introduction These 3 presentations cover the fundamental theory of electron microscopy In presentation #1 we cover: – the bits of optics we need to know – production of an electron beam – why we need vacuum & how we get it – the foundations of electron optics

Sites for Electron Microscopy These sites contain useful information concerning most of the range of techniques available *************************************************************** Microscopy & Imaging: Resources on the WWW (University of Arizona) i_onw3.html Everything in sight (site ?), including the Electron Microscopy Yellow Pages ! **************************************************************

***************************************************** Gina Sosinskys EM Outreach program: Based at the Supercomputing Center at San Diego, this site includes a very full set of Web-based lecture notes. Good text, but sadly, Gina has had problems getting many microscopists to agree to copyright release for their work, so for the moment the illustrations are rather minimal. One slight mis-statement, it is said that shadowing usually gives much worse resolution than negative staining. Not true. *****************************************************

Analytical Imaging Facility at Albert Einstein College of Medicine: Concentrates heavily - as you would expect - on the analytical side of microscopy. All types are considered, light and electron microscopy being integrated together. As you might expect from the Albert Einstein, this site is a fantastic resource *****************************************************

Helen Saibils home page: Lovely images and some movies of selected protein-based systems, including chaperonin (GroEL - GroES) and pore-forming toxin (pneumolysin) *****************************************************

UNSWs Image Gallery: Slanted towards histology in the biology section, but good images *****************************************************

**************************************************** University of Sussex - EM site some good teaching material at a simple level, as well as some pretty images. ****************************************************

and you can of course go on almost for ever, if you enter electron microscopy into a search engine (SCIRUS is good for science) so now, on to the basics......

imaging with a simple lens

the meaning of focal length

when we image a simple point

definition of resolution

the electron gun

wavelength & voltage

why high vacuum ?

how does a diffusion pump work?

the electromagnetic lens

the transmission electron microscope

The TEM Column _ Gun emits electrons _ Electric field accelerates _ Magnetic (and electric) field control path of electrons _ Electron 200KeV 2x m _ Resolution normally 200KeV 2 x m 2Å