COUNTING RATE VARIATIONS OF GAIN AND RESOLUTION IN PHOTOMULTIPLIERS OF THE RCA 6810A TYPE

Journal Article · Tue Jan 01 04:00:00 EST 1963 · Nucl. Instr. Methods

DOI:https://doi.org/10.1016/0029-554X(63)90087-9· OSTI ID:4749926

Michaelis, W; Schmidt, H; Weitkamp, C

The variations in gain and resolution of RCA 6810A photomultiplier tubes were investigated with reference to changes in the illumination of the photocathode. The tubes were mounted to a NaI(Tl) crystal and irradiated with gamma rays of different energies and intensities. Changes in the counting rate result in reversible fast and slow variations in gain. An increase of the irradiation level causes a rapid positive initial change wtth a continuing slow rise followed by a gradual decline to a stable level. Magnitude and exact time dependence vary with multiplier load and past history. Moreover, the amplitude is different for every tube. A reduction of counting rate results in a sudden negative initial shift with a continuing slow decrease. The long-term instabilities are discussed in detail. They may be attributed to reversible changes in the secondary emission ratio of the dynode surfaces. The resolution was found to deteriorate with increasing irradiation intensity. (auth)

• Research Organization: Kernforschungszentrum, Karlsruhe, Ger.
• NSA Number: NSA-17-014671
• OSTI ID: 4749926
• Journal Information: Nucl. Instr. Methods, Journal Name: Nucl. Instr. Methods Vol. Vol: 21
• Country of Publication: Country unknown/Code not available
• Language: German

Related Subjects

CATHODES
EFFICIENCY
ELECTRODES
EMISSION
INSTRUMENTS AND INSTRUMENTATION
IRRADIATION
MULTIPLICATION FACTORS
PHOTOMULTIPLIERS
RESOLUTION
SCINTILLATION COUNTERS
SODIUM IODIDES
SURFACES
THALLIUM