Radioactive Organic Bromo-Compounds

Abstract

CONSIDERABLE attention has recently been focused on the use of artificially radioactive substances in biological work. The radioactive isotope ⁸²Br has been chosen by us because it has a conveniently long half-life (34 hours), it is chemically reactive, it gives off gamma-rays which aid in its detection, and finally, it can be prepared from ⁸¹Br either by the action of slow neutrons or deuterons. Slow neutrons are easily available from the radon-beryllium reaction. Fast deuterons from the cyclotron or any other suitable high-energy source may be used either as projectiles themselves or for the production of slow neutrons as in the lithium reaction below. The relative abundance of ⁸¹Br in natural bromine is 49.3 per cent. Contamination of radioactive ⁸²Br by other isotopes is of no consequence since bromine forms no non-bromine radioactive elements on bombardment by slow neutrons or deuterons¹.