Amorphous Red Phosphorus Research Articles

Aberrant Tissue Developments in Rats Exposed to Beta Rays

As beta rays are commonly emitted by the products of a chain-reacting uranium pile, it was decided to investigate their biological effects. Suitable beta-ray sources, technics of exposure, and methods of dose measuring were developed by Raper, Zirkle, and Barnes (1). Raper, Henshaw, and Snider have reported the effects of these phosphorus beta rays on the surface organs of rats and mice (2, 3). The biological effects described by them were primarily the more immediate (or acute) effects of irradiation. Since the writing of the reports mentioned above,4 clinical observations of the experimental rats have been carried forward by the present authors. In doing so, it was found that the terminal condition of the animals was, for the most part, a remarkable display of malignant activity and developmental abnormalities. This paper, then, will be devoted to a description and discussion of these final manifestations of beta-ray injury. Some preliminary comments on methods are necessary, however, since the detailed report on beta-ray exposure technics is not now generally available. Methods and Procedures P32 was utilized as a source of beta rays in all the present experiments, this isotope being chosen from the list of beta-ray emitters after a consideration of such factors as availability, half life, and purity of radiation. To prepare P32, the reaction p31 (n,γ)P32 was used, with the pile serving as a neutron source (4). Since this isotope in a powdered form would have been virtually impossible to handle, equal partsby weight of amorphous red phosphorus and a phenolic-formaldehyde resin were combined and cast into sheets roughly 0.2 inch thick. Plaques of suitable dimensions were then cut from these sheets, activated, and used as sources. Doses of beta radiation were expressed in rep. (roentgen equivalent physical), which is described as that quantity of beta radiation which produces ionization in tissue equivalent to 1 r. Several devices were used to measure the ionization produced by the emission from the activated plaques, the basic instrument being an extrapolation chamber similar to those described by Failla (5) and Quimby (6). The essential features of this instrument were (a) two parallel charged plates and (b) provisions for varying the distance between electrodes. With the use of this chamber and absorbers of different thickness, measurements of ionization were made (a) with the interplate distance varied and (b) with various thicknesses of absorber interposed between the source and the plate uponwhich the beta rays were first incident. From these measurements, an extrapolation was made to ionization per unit volume with zero air space and with zero wall thickness.

The Atomic Distribution in the Allotropic Forms of Phosphorus at Different Temperatures

Monochromatic x-ray diffraction patterns of liquid yellow phosphorus, amorphous red phosphorus and amorphous black phosphorus were obtained, using Mo Kα radiation. The effect of temperature upon these patterns was investigated for the first two forms. Analysis of these patterns led to the determination of the atomic distribution curves in each case. The number of nearest neighbors is three for all forms. This is taken as direct proof of the existence of P4 molecules in liquid yellow phosphorus. Comparisons are made of the atomic distribution curves of each form and at the different temperatures for liquid yellow and amorphous red phosphorus.