ASSAYING OF TARGETS FOR NUCLEAR MEASUREMENTS WITH A GRIDDED IONIZATION CHAMBER
An ionization chamber with a Frisch grid is used to determine both the energy (E) of the charged particles emitted from the sample positioned coplanar with the cathode, and the cosine of the emission angle (theta') with respect to the normal of the cathode. Using the combined information on cos theta' and E, problems in particle counting due to sample absorption and scattering effects can be circumvented and sample source strengths are readily determined to an accuracy of 0.3 %. However, it is emphasized that the source strength can be determined from the particles emitted in a large solid angle close to 2 pi steradian, which means a considerable higher efficiency than for the conventional low geometry counting techniques. Moreover the present method, within reasonable limits is insensitive to source shape and thickness homogeneity. The technique will be illustrated by measurements of alpha particles and fission fragments emitted from a set of four vacuum evaporated UF-4, three electrodeposited and one suspension sprayed 235-U-3O-8 layers. The energy and angular distributions of alpha particles and of the heavy alpha recoils emitted from a self transferred 224-Ra source is discussed. The low energetic alpha recoils might be useful as probes for the investigation of ultrathin (< 400 ANGSTROEM) layers.
Bibliographic Reference: 12TH WORLD CONFERENCE OF THE INTERNATIONAL NUCLEAR TARGET DEVELOPMENT SOCIETY (INTDS), ANVERS (BELGIUM), SEPT. 25-28, 1984 WRITE TO CEC LUXEMBOURG, DG XIII/A2, POB 1907, MENTIONING PAPER E 31814 ORA
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Record Number: 1989123020400 / Last updated on: 1987-01-01
Available languages: en