Vacuum and Scientific Americans Amateur Scientist Column
A brief survey of relevant articles through the C. L. Stong era
The Amateur Scientist column in Scientific American, when it was alive and well under the leadership of C.L. Stong, contained a number of vacuum related projects. The compendium The Scientific American Book of Projects for the Amateur Scientist (Simon and Schuster, NY, 1960) contained a number of columns from the late 1950s. Two of particular interest are the ones on an electron accelerator and homemade cold cathode x-ray tubes. The former, contributed by Franklin Lee, was the first project to use converted refrigeration compressors and a simple glass mercury diffusion pump (Kurth-Ruggles design) to produce high vacuum in an amateur project. Lees voltage source was a fairly large van de Graaff generator that could charge its sphere to a potential of 500 kV.
Lees project prompted the formation of Morris & Lee, a company that supplied van de Graaff kits, vacuum pumps and various accessories. Later columns incorporated many of Lee's techniques. Specific projects detailed in these columns included:
- He-Ne laser: 9/64 with an addendum in the 12/65 issue
- High altitude chamber for biological studies: 9/65
- Hand pumped discharge tube: 8/66
- Argon gas laser: 2/69
- Molecular beam apparatus and mass spectrometer: 7/70
- Proton & deuteron accelerator (along the lines of Lees machine): 8/71
- CO2 laser: 9/71
- Two transmission electron microscopes: 9/73
- N2 laser: 6/74
- Mercury-vapor ion laser: 10/80
The molecular beam apparatus and mass spectrometer are elegant little designs and it is hoped that tBJ will have updated versions in the near future. The electron microscopes were built by students at a private high school in Chicago. One used a cold cathode electron source with a simple (one element) lens to produce a maximum magnification of about 100x. The other used a filament to produce the electrons and had three lenses (condenser, objective and projection) to provide magnifications to 10,000x.
A later Scientific American compilation, Light and Its Uses (W.H. Freeman, 1980) contained the above mentioned laser articles along with 21 other projects concerning lasers, holograms, interferometers and spectrographic instruments.
Stongs predecessor at Scientific American, Albert Ingalls, produced the classic three volume series Amateur Telescope Making. While mostly not dealing with vacuum, Book 2 of the series (1944) includes a chapter on aluminizing mirrors by John Strong of Caltech. Strong, as you may remember, was the author of Procedures in Experimental Physics, now available through Lindsay Publications. This chapter also provides notes on the aluminizing of the 100 inch Mt. Wilson mirror. In an afterward, Ingalls noted:
John Strong is not (that is, not yet-1944) yet an amateur telescope maker (ATM) though hopes are perennially entertained by the present writer. He has, however, been so close to Russell Porter (the 'patron saint' of ATMs and the designer of much of the mechanical structure of the 200 inch Palomar telescope)...that the amateur's outlook has rubbed off on him.
Book 3 (1953) offers a chapter on high vacuum equipment by Earle R. Brown of Farrand Optical Company. Here there are some good ideas on feedthroughs, valves and other improvised hardware. Also covered are evaporation techniques for various materials other than aluminum and general information on lens coating, interference filters and the cleaning of optics.
Browns introduction is interesting and relevant to this day. He says:
Every TN (Telescope Nut) has probably had the desire to aluminize his own mirrors and anti-reflection coat his own lenses...but has felt that the equipment for doing this work was so complicated and expensive that it was not worth while... Coating lenses and aluminizing mirrors, however, is only a small part of the work which can be performed by high vacuum equipment, and the processes of which it is capable offer a fascinating field for the TN with his mechanical ingenuity and intellectual curiosity.... Not the least of the appeal of high vacuum to the TN is its natural perversity. Compared to high vacuum systems, the most recalcitrant optical surface is a paragon of meek submissiveness. This sort of thing makes raving maniacs of most people, but TN's are of the peculiar breed of cat which thrive on frustrations.
During Ingalls tenure as editor the Amateur Scientist column, he did include one vacuum related article, one on constructing a cyclotron (9/53). A group of teen-agers from El Cerrito, California made the cyclotron over a period of a couple years with improvised components, some donated parts, plenty of professional advice and a tremendous amount of determination.
After Stongs death, the Amateur Scientist went into a long period of decline. Toward the end of 1995 it was revived as a regular feature under Shawn Carlson, executive director of the Society for Amateur Scientists where it continued until being retired again in 2001.
All of the Amateur Scientist articles (over 1000) are now available on CD-ROM through the Society for Amateur Scientists. Information is on their Website. Get it, you wont be sorry.
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