INVESTIGATION OF ACTIVATOR DISTRIBUTION IN NaI-Tl CRYSTALS

Journal Article · Thu Jan 01 04:00:00 EST 1959 · Ukrain. Fiz. Zhur.

OSTI ID:4241660

Belikovich, B O; Vishnevskii, V N; Liskovich, O B; Pidzirailo, M S

Sodium iodide crystals, thallium activated, were grown from a melt by a modification of Kyropoulos's method. Along with the regulated lateral heater, the furnace contained an independently regulated bottom heater. Crystals about 40 mm in diameter and length were taken for concentration investigations. The thallium concentration in various regions of the grown crystals was determined by the strength of optical absorption at the maximum of the long-wave absorption band of the activator. The activator content of the crystals proved to be 7 to 12 times less than that of the charge. Thallium is distributed somewhat unevenly through the crystal volume: the later the crystal region is formed in the growth process, the lower the thallium content. The longitudinal and radial concentration gradients do not, in general, exceed 10%/cm. In some crystal zones the activator distribution is practically uniform in the radial direction. The latter fact evidently indicates that on applying a regulated bottom heater in ihe crystal growing furnace, such thermal conditions may be created that the crystal growth front acquires the most advantageous form from the standpoint of uniformity of activator distribution in the crystal. The presence of a relatively small concentration gradient in the investigated crystals indicates that almost the entire effective volume of the crystals grown by the applied method may be utilized as a scintillator. (auth)

• Research Organization: Originating Research Org. not identified
• NSA Number: NSA-13-017906
• OSTI ID: 4241660
• Journal Information: Ukrain. Fiz. Zhur., Journal Name: Ukrain. Fiz. Zhur. Vol. Vol: 4
• Country of Publication: Country unknown/Code not available
• Language: Ukrainian

Related Subjects

ABSORPTION
ACTIVATION
CHEMISTRY
CRYSTALS
ENRICHMENT
FURNACES
HEATING
MELTING
QUANTITY RATIO
SCINTILLATIONS
SODIUM IODIDES
THALLIUM