Photomultiplier Tubes
Connecting a Photomultiplier Tube (PMT) to a telescope is standard practice in Stellar Photometry. You will find a wealth of information about selecting and using a PMT in the references at the bottom of this page.
Instead of rehashing the reference material, I will focus on the key points about this application.
The PMT is a glass vacuum tube. It is very fragile. The PMT requires a special socket, called a voltage divider socket. The socket is prewired to correctly bias the PMT stages when high voltage is applied. Ideally, tube and socket are purchased as a pair. I bought the PMT and socket from O. E. Technologies: a dealer specializing in used scientific equipment. They have a detailed catalog, reasonable prices and helpful technical support. Their web page is here: OE TECH. Another place to find PMT's is in the Astromart Classifieds. By placing a free "wanted" ad, you should receive several offers from amateur astronomers.
The PMT requires a source of negative high voltage, approximately -1000 volts. The power supply must be extremely stable and have low ripple. The gain of a PMT changes dramatically with voltage, and supply ripple at 60 Hz is totally unacceptable. There are plans in some of the references for building a power supply. But consider this: Do you really want to be tinkering with a -1000 volt homebrew power supply? I purchased a used Hewlett-Packard power supply, made for the purpose, for about $150.
The RCA-7764 photomultiplier tube was chosen primarily for its small 3/4 inch diameter size and the "head-on" configuration of the photocathode. ("Head-on" means light shines on the end of the tube, instead of the side.) The small diameter "head-on" tube fits in the telescope's 1.25 inch eyepiece holder with a simple cylindrical adapter made of black Delrin plastic, adding minimal weight. A pinhole aperture (4 mm diameter) is mounted a small distance from the face of the tube to reduce the field of view and minimize sky background counts. The aperture was sized such that a star requires at least 10 seconds to drift across the active area. ( Photometric data is always taken with the telescope's tracking drive off, and for a minimum of 10 seconds.) Here is everthing I know about the RCA-7764. Please contact me if you have the RCA data sheet: Email Author.
References for PMT's
Hamamatsu publishes a catalog titled "Photomultiplier Tubes". The first 18 pages of the catalog is packed with technical information on PMT tubes and how to use them. Search the web for a Sales Office and request a copy, it's worth it!
The book "Radiation Detection and Measurement", 2nd Edition by Glenn F. Knoll and published by John Wiley & Sons also has excellent information for using PMT's.
The book "Photoelectric Photometry of Variable Stars", 2nd Edition by Douglas S. Hall and Russel M. Genet has a tremendous amount of useful information, including plans for a high voltage power supply.
Another book with circuits and plans is "Zen and the Art of Photoelectric Photometry" by Jeffrey L. Hopkins. Ask your local library to order it for you using the Interlibrary Loan program.
RCA's "Photo-Multiplier Handbook", which has been reprinted by Burle Industries, as part number TP-136. It is available from Richardson Electronics at (800) 348-5580.