| 摘要 |
1,253,547. Densitometer photo-multiplier arrangement. GAF CORP. Dec. 11, 1968 [Dec. 12, 1967], No.58924/68. Heading G1A. In a densitometer having a photo-multiplier 10 exposed to light 11 from a specimen and fed by a variable dynode voltage supply 14, the photomultiplier output is maintained constant by a loop in which it is compared with a reference voltage, controlling the variable dynode supply, the dynode voltage being indicated or recorded as a measure of optical density. The reference voltage at terminal 23 is compared with the photomultiplier output in an operational amplifier 20, and the dynode voltage is applied to the indicator or recorder across a voltage divider 37, 38. |
