An inexpensive solid-state photometer circuit useful in studying bioluminescence

Abstract

Abstract : Bioluminescence has been the subject of much research within the past two decades. Measurement of this phenomenon has usually been by a photomultiplier photometer originally designed by MacNichols in 1952 and subsequently modified by Mitchell and Hastings, Strickland, and others. There are many commercially designed photometers that are adequate but unfortunately are quite expensive. Assembly of a suitable instrument from commercially available parts is also expensive and time-consuming, requiring a considerable degree of technical ability. Recently, inexpensive integratd photodetection assemblies (IPA) have become available from the Radio Corporation of America. These assemblies, complete with an RCA type 931B photomultiplier tube and integral solid-state high-voltage power supply, voltage regulator, and a resistor divider network, are mounted behind an electrostatic shield. Additionally, low-cost solid-state operational amplifiers can be used to convert the current output of the IPA to voltage and to interface with conventional recording instrumentation and in integration. Finally, inexpensive solid-state power supplies, adequate to drive both the IPA and the operational amplifiers, are available.