Improvements to the on-line mass separator, RAMA, and the beta-delayed charged-particle emission of proton-rich sd shell nuclei

Thesis/Dissertation · Fri Mar 01 04:00:00 EST 1996

DOI:https://doi.org/10.2172/286266· OSTI ID:286266

Ognibene, Theodore Joseph ^[1]

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1. Lawrence Berkeley National Lab., CA (United States). Nuclear Science Div.

To overcome the extreme difficulties encountered in the experimental decay studies of proton drip line nuclei, several techniques have been utilized, including a helium-jet transport system, particle identification detectors and mass separation. Improvements to the ion source/extraction region of the He-jet coupled on-line Recoil Atom Mass Analyzer (RAMA) and its target/ion source coupling resulted in significant increases in RAMA efficiencies and its mass resolution, as well as reductions in the overall transit time. At the 88-Inch Cyclotron at LBNL, the decays of ³¹Cl, ²⁷P and ²⁸P, with half-lives of 150 msec, 260 msec and 270.3 msec, respectively, were examined using a he-jet and low-energy gas ΔE-gas ΔE-silicon E detector telescopes. Total beta-delayed proton branches of 0.3% and 0.07% in ³¹Cl and ²⁷P, respectively, were estimated. Several proton peaks that had been previously assigned to the decay of ³¹Cl were shown to be from the decay of ²⁵Si. In ²⁷P, two proton groups at 459 ± 14 keV and 610 ± 11 keV, with intensities of 7 ± 3% and 92 ± 4% relative to the main (100%) group were discovered. The Gamow-Teller component of the preceding beta-decay of each observed proton transition was compared to results from shell model calculations. Finally, a new proton transition was identified, following the β-decay of ²⁸P, at 1,444 ± 12 keV with a 1.7 ± 0.5% relative intensity to the 100% group. Using similar low-energy detector telescopes and the mass separator TISOL at TRIUMF, the 109 msec and 173 msec activities, ¹⁷Ne and ³³Ar, were studied. A new proton group with energy 729 ± 15 keV was observed following the beta-decay of ¹⁷Ne. Several discrepancies between earlier works as to the energies, intensities and assignments of several proton transitions from ¹⁷Ne and ³³Ar were resolved.

• Research Organization: Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE Office of Energy Research (ER)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 286266
• Report Number(s): LBNL--38848; ON: DE96012908
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ACCELERATOR FACILITIES
ALPHA DECAY
ARGON 33
BEAM OPTICS
BETA DECAY
CHARGED PARTICLE DETECTION
CHLORINE 37
DAUGHTER PRODUCTS
DELAYED ALPHA PARTICLES
DELAYED PROTONS
GAMOW-TELLER RULES
HELIUM
ISOTOPE SEPARATORS
NEON 17
PHOSPHORUS 27
PHOSPHORUS 28
PROTON-EMISSION DECAY
RADIATION DETECTORS
REACTION PRODUCT TRANSPORT SYSTEMS
SILICON 25
TARGET CHAMBERS