抄録
Special precautions should be given to the handling of ultra-dilute solution of P^<32>O_4 and the determination of its intensity by plant ash as such. As revealed from Table I and Fig. 1,the absorption error of P^<32>O_4 on the surface of glassen ware sometimes oversteps the allowable limit of experimentation, when its contact proceeds at such ultradilution as is often the case in diluting H_3P^<32>O_4 sample of high specific activity. Practically, 0.5 p.p m. addition of inert PO_4 as carrier proved sufficient to minimise this reduction to negligible extent. Table 2,3,4 and Fig. 2,3,4,5 show the absorption effect of plant ash in the determination of P^<32> β-ray by Geiger-Muller Counter. Despite the powerful maximum energy of β-ray emitted from P^<32> (1.67 MeV.) self absorption of plant ash containing the same specific activity of P^<32> reached ca. 3% and 5% at 20 mg and 30 mg ash per square centimeters respectively.
