mOHf/ BACKGROUND OF
LESS THAN 1 CPM!
with T/A's New Model LLB-40 Low Level Beta System
Model LLB-40 Low-Le»el Beta System with Model PT-1R Predetermined Timer
Offers All the advantages of Amperex* Beta Counter... • A single cosmic ray guard tube replaces the multi-tube array previously required in low background systems. • Only 1200 lbs. of shielding are needed.. in place of the 3000 lbs. of shielding normally required in low background systems • Simplified circuitry, plus the elimination of multi-guard tube malfunctions, provides greater system reliability.
SAMPLE DRAWER in open position, showing planchet elevator assembly
• The beta detection efficiency of the Amperex tube substantially exceeds that obtained by any previous halogen-quenched tube. • Because of its unique construction, the cosmic ray efficiency of the guard counter is virtually 100%.
m/\
these T/A Exclusive Design Features! 9H
decent
ueaAO-, the measurement of low
level radiation has become increasingly important, especially with regard to radioactive contamination of the atmosphere, water supplies, and food-stuffs, as well as all laboratory applications involving the counting of low-activity beta samples. Hence, an acute need has developed for a reliable, ultra-sensitive low-level beta system, such as the T/A Model LLB-40, which combines extreme accuracy and compactness at a moderate cost.
For complete information, write for BULLETIN N O . 1 7 3 .
• T/A's unique combination of lead, steel, and mercury shielding enables the Amperex guard counter to achieve optimum background reduction.
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• T/A's unique single-action sample drawer with automatic elevator assembly provides sample/detector geometry that is reproducible within .002" vertically and .005" horizontally. • T/A's specially designed anti-coincidence scaler includes separate beta and guard channels, built-in elapsed time indicator, high voltage power supply, provision for utilizing predetermined timer, and provision for external high speed scaler. Guard channel switch permits monitoring of either the guard tube or the beta counter tube before anti-coincidence.
TECHNICAL ASSOCIATES Instrumentation
for Nuclear
Research
140 WEST PROVIDENCIA AVENUE —BURBANK, CALIFORNIA Circle No. 161 on Readers' Service Card 86 A
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ANALYTICAL CHEMISTRY
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