418 



RADIOISOTOPES IN BIOLOGY AND AGRICULTURE 



Table 10-1. Sensitivities of Radioactivation Analysis in ORNL Graphite 



Reactor" {Continued) 



Element 



Osmium 



Palladium 



Phosphorus. . . 



Platinum 



Potassium 



Praseodymium . 



Rhenium 



Rhenium 



Rubidium 



Ruthenium .... 



Ruthenium .... 



Samarium 



Scandium 



Selenium 



Silicon 



Silver 



Sodium 



Strontium 



Sulfur 



Tantalum 



Tellurium 



Terbium 



Thallium 



Thulium 



Tin 



Tungsten 



Ytterbium 



Yttrium 



Zinc 



Zirconium 



Zirconium 



Iso- 

 tope 

 pro- 

 duced 



Osl93 



pdl09 



p32 



ptl97 



K42 



Pj-142 



Rei8« 

 Re "8 

 Rb86 

 Rui«3 



Rui«5 



Smi53 



Sc« 

 Se^i 

 Si" 

 Agiiom 



Na" 



gj.S7m 



Ta"2 

 Tel" 

 Tb"" 



'PJ204 



Tmi"" 



Sni2i 



Wris7 



Y90 



Zn^s 

 Zr« 

 Zr" 



Half-life 



30.6 

 13.6 

 14.3 

 18 



hr 

 hr 



days 

 hr" 



12.44 hr 

 19.2 hr 

 3.87 days 



16.9 

 19.5 

 39.8 

 4.5 

 47 

 85 

 17 



hr 



daj's 



days 



hr' 



hr 



days 



min 



2 . 62 hr 



270 days 



15.06 hr 



2.8 hr 



87.1 



115 



9.3 



73.5 



3.5 



129 



1.1 



24.1 



102 



days 



days 



hr 



days 



yr 



days 



da.ys 



hr' 



hr 



2 . 54 days 

 57 min 

 65 days 

 17 hr 



"Atomic" 



cross 



section, 



barns 





1.0 

 3.1 

 0.029 

 0.28 

 0.067 

 10 

 37 



47.2 

 0.52 

 0.38 

 0.12 

 36 

 14.4 

 0.23 

 . 0037 

 1.1 

 0.4 

 0.13 

 . 0052 

 21 



0.15 

 22 

 2.25 

 100 

 0.072 

 9.9 

 15 

 1.24 

 0.20 

 0.06 

 0.045 



% 

 satura- 

 tion, 

 1 month 



76.7 



99.5 



65.6 

 39.0 



21.5 



7.0 



21.2 

 16.2 



26 

 2.0 

 15.0 



99.3 



27.3 



Sensitivity, 



Mg of 



element 



0.03 



0.005 



0.02 



0.1 



0.08 



0.002 



. 0007 



. 0006 



0.03 



0.1 



0.1 



0.0006 



0.002 



0.05 



1 



0.11 



0.007 



0.6 



4 



0.007 



0.1 



0.004 



0.6 



0.002 



0.2 



0.003 



0.002 



0.01 



0.04 



0.7 



0.3 



" Based on 5 X 10" neutrons/cm Vsec. 



(From G. W. Leddicotte, and S. A. Reynolds, Neutron Activation Analysis, A 

 Useful Analytical Method for Determination of Trace Elements ORNL-1443 Feb 23 

 1953.) ' ' • - 



available from each. It will be recalled from Eq. (10-1) that the sensitiv- 

 ity is directly proportional to the flux. Thus, for example, if 0.007 Mg 

 sodium can be detected with a flux of 5 X 10", then 35 ^g will be required 

 for detection if the flux is 10^ Thus the sensitivities listed in Table 10-1 

 can readily be calculated on the basis of the fluxes hsted in Table 10-2. 



