• Equipment Coming. Small labora tory neutron generators, says Dr. Meinke, will bring the cost of a neutron source d o w n to around $20,000. And such units are in the works at several companies, among them Texas Nuclear, Nuclear-Chicago, Schlumberger, Kaman Aircraft, and High Voltage E n g i neering. Texas Nuclear, for one, now markets a generator which might b e u s e d for activation analysis. T h e main problem, explains Dr. M e i n k e , is getting a high enough flux in the generator for this t y p e of w o r k . H o w e v e r , he says, units should he avail able within a year that will permit anal ysis of as little as 1 microgram of vanadium. (Using the university's F o r d Nuclear Reactor, Michigan re searchers can detect 0.01 to 0.001 mi c r o g r a m of vanadium.) S u c h generators operate by accelerat ing deuterons through 100,000 volts. These strike a target of tritium adsorbed on zirconium. The reaction gives 14 m.e.v. neutrons which a r e then mod erated to thermal energies. • Fast Methods. Looking a t t h e other stumbling block, t h e time con READY FOR ANALYSIS. G r a d u a t e student at University of Michigan puts a freshly s u m e d , Dr. Meinke points out that un irradiated oil sample into a measurement container w h e r e it will be analyzed til analyses can be m a d e within LI clay, for vanadium. Laboratory neutron generators should b e available within activation analysis won't get very far as a year t h a t will permit analysis of as little as 1 microgram of v a n a d i u m . O n e w a y to Companies working on t h e units include Texas Nuclear a n d Nuclear-Chicago a common technique. s h o r t e n the time is to analyze for iso topes with a short half-life. But here, says Dr. Meinke, the prob l e m is to make a fast separation before t h e isotope has decayed to too low a level to measure. Michigan research ers have devised ways to do tliis for isotopes of vanadium, rhodium, cop Equipment, methods b e i n g d e v e l o p e d could m a k e acti p e r , a n d silver in samples that have been irradiated for six minutes. Vana v a t i o n analysis a commonly used technique d i u m , for example, can b e separated in four minutes, silver in five. D I P P I N G into his arsenal of weapons, show promise of removing these road T h e university is not stopping here; the analytical chemist has generally h a d blocks. Dr. \Y. W a y n e Meinke of the it plans to develop procedures for still to bypass activation analysis—it costs University of Michigan told the 7th other elements with short half-life iso too much and takes too long. But Detroit Anachcni (Association of An t o p e s . On its list: aluminum, scan T h e d i u m , manganese, indium, iodine, dys equipment a n d methods being devel alytical Chemists) Conference. oped today may soon p u t the technique result will be a commonly used analyt prosium, and thorium. ical technique for certain trace elements within his reach. University researchers are also work To make use of activation analysis, that gives high sensitivity and does ing o n more ways to put activation anal the analyst must irradiate his sample away with the need for blanks in the ysis to use. Some of the materials with neutrons. Today this means a determination. it h a s already been used for include nuclear reactor or high energy s o u r c e I n activation analysis. Dr. Meinke silver, rhodium, and indium in meteor e q u i p m e n t costing upwards of at least explains, a sample is first irradiated. ites; vanadium, arsenic, molybdenum, 8100,000, often much more. And it This is usually followed by chemical tungsten, and gold in marine ashes often means irradiation times running separation of the element being an ( s u c h as seaweed and s h r i m p ) ; cobalt, alyzed. The element's activity is then copper, and vanadium in rat liver and from overnight to several days, or even counted, measured in a g a m m a ray k i d n e y tissues; v a n a d i u m in. crude weeks. Laboratory neutron generators and spectrometer, and correlated with a petroleum and in cracking catalysts; and niobium in rock. Ε fast radiochemical separation methods known standard.
RESEARCH
Activation Analysis G r o w s
40
C&EN
NOV.
9.
1959
