Filters
Results 1 - 1 of 1
Results 1 - 1 of 1.
Search took: 0.023 seconds
AbstractAbstract
[en] The spectra of nuclear γ rays emitted in coincidence with π- absorption events in carbon, nitrogen, sodium, sulfur, and calcium, were taken with a Ge(Li) detector. Yields of excited states of daughter nuclei were determined, recoil momenta were computed, and the mean number of γ rays produced per π- stop was measured. Gross features of the spectra of daughter nuclei from 32S and 40Ca are explained by a model which assumes a combination of absorption on pairs plus small residual excitation, and uniform distribution of the pion's rest energy in the nucleus, followed by statistical evaporation. Some preference for excitation of high-spin states was seen. One-nucleon removal was strongly suppressed except in the case of the sodium target. An analysis of Doppler broadening indicated that nuclei of 12C in the 4439-keV state produced from π- absorption on 14N have mean recoil momenta of (169 +- 6) MeV/c. This agrees with a simple calculation which assumes absorption on a deuteron. Ratios of np- to pp-removal yields were found to be about 1 for 32S and 40Ca, and about 3 for 23Na. Theory predicts 3, which can be reconciled with the 32S and 40Ca results by correcting for enhancement of 2+ states of even-even nuclei. Three-nucleon removal is prominent for both 32S and 40Ca, and there are anomalously large yields for states corresponding to transfer of the odd neutron to the f/sub 7/2/ shell. Appreciable yields are also seen for removal of the equivalent of one or more α particles from 32S and 40Ca. 28Si produced from 32S, and 36Ar and 28Si from 40Ca display large recoil momenta. These two, together with the observation of the production of high-spin states, are suggestive of absorption on larger aggregates of nucleons, perhaps α clusters
Primary Subject
Source
1976; 216 p; University Microfilms Order No. 76-11,179.; Thesis (Ph. D.).
Record Type
Report
Literature Type
Thesis/Dissertation
Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue