Simultaneous measurement of {sup 4}He({gamma},p)/({gamma},n) with tagged photons
Journal Article
·
· Bulletin of the American Physical Society
OSTI ID:387048
- and others
There has been considers controversy regarding the two-body photodisintegration cross section of {sup 4}He, By charge symmetry, the ratio {sigma}({gamma},p)/{sigma}({gamma},n) is expected to be near unity for E{sub {gamma}} < 35 MeV, although a review of earlier data suggests deviations as large as a factor of 2 in the individually measured cross sections. Recent ({gamma},p) data, however, are in good agreement with the earlier ({gamma},n) results and appeared to resolve this issue. We have addressed this question directly by performing the first simultaneous measurement of the absolute cross sections for {sup 4}He({gamma},p) and {sup 4}He({gamma},n) using monoenergetic (tagged) photons of energy E{gamma} = 25-60 MeV. The two-body channels were unambiguously identified by detecting the {sup 3}H and {sup 3}He recoil fragments simultaneously at {theta}{sub lab} = 90{degrees} in {Delta}E-E telescopes consisting of windowless gas proportional counters backed by large-area solid-state detectors. Using helium as both a target and an ionization gas facilitated the detection of the low-energy recoil particles. Absolute cross sections for both channels will be presented, and ratios will be compared to recent model calculations.
- OSTI ID:
- 387048
- Report Number(s):
- CONF-931044--
- Journal Information:
- Bulletin of the American Physical Society, Journal Name: Bulletin of the American Physical Society Journal Issue: 9 Vol. 38; ISSN BAPSA6; ISSN 0003-0503
- Country of Publication:
- United States
- Language:
- English
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