Automated uranium analysis by delayed-neutron counting

Automated uranium analysis by fission-induced delayed neutron counting is described. A short description is given of the instrumentation including transfer system, process control, irradiation and counting sites, and computer operations. Characteristic parameters of the facility (sample preparations), background, and standards) are discussed.

A sensitivity of 817 ± 22 counts per 10-6g U is found using irradiation, delay, and counting times of 20 s, 5s , and 10 s, respectively. Presicion is generally less than 1% for normal geological samples. Critical level and detection limits for 1.o g samples are 8 and 16 ppb, respectively. The importance of some physical and elemental interferences are outlined.

Dead-time corrections of measured count ratos are necessary and a polynomical expression is used for count rates up to 105. The presence of rare earth elements is regarded as the most important elemental interference. A typical application is given and other areas of application are described.