Radioactivity and Nuclear Reactions Applied to Astrophysics, Particle Physics, Archeology, and the Study of Art Works 1947-67

Radioactivity applied to archaeology and to the study of works of art

The first application of neutron activation analysis to the study of archaeological materials was made at BNL. In some Greek terra cotta figurines it was found that the trace impurity compositions fall into patterns which are correlated to locations of origin and manufacture. Ancient commerce in Roman Aretine pottery, in South Arabian pottery, and in Mayan pottery has been traced. An extensive study of ancient glass has revealed many facts concerning the technology of its manufacture. A number of institutions have now adopted neutron activation techniques for work in these areas. It was at BNL that activation autoradiography was for the first time applied to investigations of works of art such as paintings and to recovery of images from badly faded historic photographs. In paintings, the different pigments give rise to radiations decaying with different half-lives, and a sequence of autoradiographs may provide information about layers of pigments used by the artist and about his techniques of application.

E. V. Sayre, "Some Ancient Glass Specimens with Compositions of Particular Archaeological Significance," BNL 879 (T-354), July 1964.
E. V. Sayre and H. N. Lechtman, "Neutron Activation Autoradiography of Oil Paintings," Studies in Conservation 13, 161 (1968).

Lepton conservation

The neutrino capture reaction, n+ Cl37 Ar37 + e-, was shown not to proceed with the antineutrinos emitted by a nuclear reactor, thus experimentally demonstrating that neutrinos and antineutrinos differ in their interactions with nuclei. This result is one of the prime experimental facts supporting the principle of lepton conservation.

R. Davis, "An Attempt to Observe the Capture of Reactor Neutrinos in Chlorine-37," Proc. 1st UNESCO Conf., I, 728 (1958).

Application of radioactivity and nuclear reactions to astrophysics

Measurements have been made of the stable and radioactive products produced in meteorites by cosmic radiation. From these measurements and from the high energy production cross sections for these products it is possible to obtain information about the cosmic ray intensity. Two important conclusions have been made: 1) the intensity of cosmic radiation has been constant in time, that is, the average intensity over the last 400 years is the same as the average intensity over the last 400,000 years; 2) the intensity of the cosmic. Radiation near the earth is about 20 percent lower than the intensity at several earth-sun distances from the sun.

The Cl36-Ar36 method used extensively for determining accurate cosmic ray exposure ages of meteorites originated at BNL.

The time interval which elapsed between formation of the elements and formation of an earth capable of retaining atmosphere was deduced to be 2.7 x 108 years. This number is based on a BNL measurement of the half-life of I129, 1.72 x 107 years, and on the justifiable assumption that most of the Xe129 now present on earth originated from that part of the original I129 still remaining to decay after the earth was formed.

An experiment is underway to test the present theory of the solar energy generation process by observation of the neutrino radiation emitted from the sun. The method used depends upon measurement of the neutrino-capture reaction n + Cl37 Ar37 + e- in a detection system containing 610 tons of the chlorine-containing compound C2Cl4. Observations show that the neutrino capture rate in the detector is at least a factor of seven below that expected from current theory.

S. Katcoff, O. A. Schaeffer, and J. M. Hastings, "Half-Life of I129 and the Age of the Elements," Phys. Rev. 82, 688 (1951).
O. A. Schaeffer, R. Davis Jr., R. W. Stoenner, and D. Heymann, "The Temporal and Spatial Variation in Cosmic Rays," Proc. Intl. Conf. on Cosmic Rays, Jaipur, India, 3, 480 (1963).
R. Davis Jr. and D. S. Harmer, "Solar Neutrino Detection by the Cl37-Ar37 Method," Proc. Informal Conf. on Experimental Neutrino Physics, CERN 65-32 (Geneva) 1965.
R. Davis Jr. and D. S. Harmer, "Solar Neutrinos," Die Umschau 2, 56 (1966).

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Last Modified: June 28, 2012