Fission Barrier of Thallium-201
Abstract
A new method involving the detection of fission fragments in mica has been applied to the measurement of the fission cross section of the compound nucleus Tl201 produced by bombardments of Au197 with helium ions. These data have been interpreted in terms of an expression for the ratio of fission to neutron-emission probabilities similar to those used conventionally, but modified to include the effect of quantum-mechanical barrier penetrability. In this way a height of 22.5±1.5 MeV was found for the fission barrier of Tl201 and a lower limit on the width could be established. The above value of the barrier, when interpreted on the basis of the liquid-drop theory, leads to an accurate determination of the ratio of the electrostatic to the surface energy of nuclei. This serves to establish the constant of proportionality between the "fissionability parameter" x and the value of Z2/A as follows: x=(Z2/A)/(48.4±0.5). This measured barrier height, when added to the ground-state mass of Tl201, gives a saddle-point mass of this nucleus equal to 200.9949±0.0015 mass units (carbon scale).
Additional Information
©1964 The American Physical Society Received 23 December 1963 The work of adopting the least squares fitting program to the theoretical functions, data fittings proper, and all activities directly concerned with the computers were carried out by Claudette Rugge. Her outstnading contribution to this work deserves the highest recognition. We are grateful to Bernard G. Harvey and the staff of the 88-in. cyclotron for help and cooperation with the experimental work. We also acknowledge the valuable assistance of Jean Rees and Joan Phillips in preparing this manuscript in helping with the scanning. We are grateful to Ray Nix and John Huizenga for very valuable discussions. We appreciate the support given by the General Electric Company in enabling one of us (Price) to take part in these experiments. This work was done under the auspices of the U.S. Atomic Energy Commission.Files
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Additional details
- Eprint ID
- 5259
- Resolver ID
- CaltechAUTHORS:BURpr64
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2006-10-06Created from EPrint's datestamp field
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2021-11-08Created from EPrint's last_modified field
- Caltech groups
- Division of Geological and Planetary Sciences