BARTOL RESEARCH FOUNDATION
Characteristic Radiations of Rhodium (105)*, by C. E. MANDEVILLE AND E. SHAPIRO. The 36.8-hr. rhodium (105) was grown from its short-lived ruthenium parent when metallic ruthenium was irradiated by neutrons in the Oak Ridge pile. The target material was purified prior to irradiation by the distillation of RuO4 from a perchloric-sulfuric acid solution of RuCl8 Chemical separations for the removal of ruthenium and technetium were carried out subsequent to exposure. The beta rays have a maximum energy of N 0.6 Mev as measured by aluminum absorption, and the gamma rays were found to have an energy of 0.30 Mev when absorbed in lead. The beta-gamma coincidence rate is independent of the beta ray energy, and the magnitude suggests that the harder beta rays are coincident with soft quanta of the x-ray region. Very few beta rays are coincident with the gamma ray at 0.30 Mev. No beta-beta coincidences were detected for ranges exceeding 6 mg./cm3 No gamma-gamma coincidences were found.
* Assisted by the joint program of the ONR and the AEC. P Radiations from Cerium (144) --~ Praseodymium (144) ~ Neodymium (144),* by C. E.
MANDEVILLE AND E. SHAPIRO. Ce TM, in equilibrium with its 17-min. daughter activity, Pr TM, was separated from fission fragments at the Oak Ridge pile. After further chemical purification, coincidence, and absorption measurements were made of the emitted radiations. The beta-rays of the 300-day Ce TM were found to have a maximum energy of 0.36 Mev, and the very hard beta-rays of Pr TM have an end point at 2.87 Mev. A source of the two radionuclides in equilibrium emits X-rays at 36 key and gamma-rays having a mean energy of 1.67 Mev as determined by absorption curves in lead and aluminum. A coincidence absorption curve indicated that a hard gamma-ray at 2.60 X 0.15 Mev is emitted in the disintegration of Pr TM. The beta-gamma-coincidence rate of Pr TM was observed to decrease from an extrapolated value of 0.02 X 10 -s coincidence per beta-ray at zero absorber thickness to zero at an approximate betaray energy of 0.42 Mev. The magnitude of the coincidence rate and the calibration of the gamma-ray counter indicate that two per cent of the beta-rays of Pr TM are coupled with the hard gamma-radiation. Gamma-gamma-but no beta-beta-coincidences were found in Ce TM --prl~.
* Assisted by the joint program of the ONR and the AEC.