โ Scribed by J. Veldkamp; H. De Vries
No coin nor oath required. For personal study only.
Laboratorium der Rijks-Universiteit te Groningen Several periods have been obtained in Ru on neutron and deuteron bomhardment. Kurtschatow, Nemenow and Selinow~) found the following periods produced by slow neutrons: 40 sec, 100 sec, 11 h, and 76 h, with intensities having the ratio of 100 : 100 : I0 : 40. Livingood2) observed periods of 4h, 39h, 11 days and 46 days by deuteron bombardment. From the fact that the intensities of 40 sec and 100 sec were identical Kurtschatow concludes that there takes place a two step reaction als follows: Ru TM (n, y) -+ Ru 105 (40 sec) --~ Rh 105 (100 sec) -+ Pd 1~ This conclusion cannot be right. Calculation shows that the elements of a chain reactioal with 40 sec and 100 sec periods must have extrapolated intensities which are in the ratio of 1 : 5 and not 1 : 1.
To clear up this matter we have irradiated very pure lZu (furnished by Heraeus) with neutrons of a Philips neutron generator, having an intensity equivalent to about 2 g radium + beryllium. On bombarding with slow neutrons we found periods of 45 sec, 4 min, 4 h and 22 h, the relative saturation intensities being about 100, 10, B0 and 200. No trace of any longer period could be observed. The periods of 45 sec and 4 rain obviously must be identified with the well known Rh periods of 44 sec and 3.9 mill and are due to a small contamination of our Ru by Rh. Since the short periods of Kurtschatow (40 sec and 100 sec) are much stronger than ours as compared with the long periods, we conclude that they too are to be attributed to some impurity, most probably Rh. The investigations are being continued in order to find the possible chain reaction Ru TM --~ Ru ~~ --~ Rh ~~ -+ Pd ~~ which can very probably be caused by slow neutron bombardment.
๐ SIMILAR VOLUMES
The radioactivity of Co, Ni, Cu and Zn induced by neutrons of different energies is investigated. When bombarding Cu and Zn with fast neutrons, periods are observed which make us suppose that two neutrons are emitted by these nuclei. Experiments to confirm this presumption are described.