Development of the helium-jet fed on-line mass separator RAMA and its application to studies of T/sub z/ = -2 nuclei

Technical Report · Mon Oct 01 04:00:00 EDT 1979

DOI:https://doi.org/10.2172/5771403· OSTI ID:5771403

Moltz, D M

The study of nuclei far from beta stability is hampered greatly when the nuclide of interest decays in a manner identical to that of a nuclide produced in greater yield in the same bombardment. One solution to this problem is through the use of an on-line mass separator. Development of the Berkelely helium-jet fed on-line mass separator RAMA is discussed as applied to studies of the A = 4n, T/sub z/ = -2 nuclides. RAMA (Recoil Atom Mass Analyzer) has typical efficiencies of 0.1% for approx. 75 elements with melting points less than or equal to 2000/sup 0/C. This efficiency permits decay studies to be readily performed on nuclei with production cross sections greater than or equal to 500 ..mu..b for ..gamma..-ray spectroscopy and greater than or equal to 1 ..mu..b for discrete energy charged particle spectroscopy. The mass range on the normalized RAMA focal plane is +- 10%. The quoted efficiency is for a mass resolution of M/..delta..M approx. 300. RAMA has been used to observe two members of the A = 4n, T/sub z/ = -2 series of beta-delayed proton emitters, /sup 20/Mg and /sup 24/Si. Observation of beta-delayed protons from a mass-separated sample of /sup 20/Mg(t/sub 1/2/ approx. 95 ms) establishes the mass-excess of the lowest T = 2 (0/sup +/) state in /sup 20/Na (13.42 +- .05 MeV), thereby completing the mass twenty isospin quintet. A similar measurement of the decay of /sup 24/Si (t/sub 1/2/ approx. 100 ms) establishes the mass-excess of the lowest T = 2 (0/sup +/) state in /sup 24/Al (5.903 +- 0.009 MeV). The mass 24 isospin quintet is incomplete because the mass of /sup 24/Si remains unknown. In both cases, excellent agreement is obtained using only the quadratic form of the isobaric multiplet mass equation (IMME). 79 references.

• Research Organization: California Univ., Berkeley (USA). Lawrence Berkeley Lab.
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 5771403
• Report Number(s): LBL-9718
• Country of Publication: United States
• Language: English

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73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ALKALI METAL ISOTOPES
ALKALINE EARTH ISOTOPES
ALUMINIUM 24
ALUMINIUM ISOTOPES
BARYONS
BETA DECAY
BETA DECAY RADIOISOTOPES
BETA SPECTRA
BETA-PLUS DECAY
BETA-PLUS DECAY RADIOISOTOPES
BINDING ENERGY
DATA
DATA FORMS
DECAY
DELAYED PROTONS
EFFICIENCY
ELEMENTARY PARTICLES
ENERGY
ENERGY LEVELS
EVEN-EVEN NUCLEI
EXPERIMENTAL DATA
FERMIONS
GRAPHS
HADRONS
INFORMATION
ISOLATED VALUES
ISOSPIN
ISOTOPES
LIGHT NUCLEI
MAGNESIUM 20
MAGNESIUM ISOTOPES
MASS SPECTROMETERS
MEASURING INSTRUMENTS
MILLISEC LIVING RADIOISOTOPES
MULTIPLETS
NUCLEI
NUCLEONS
NUMERICAL DATA
ODD-ODD NUCLEI
PARTICLE PROPERTIES
PROTONS
RADIOISOTOPES
SECONDS LIVING RADIOISOTOPES
SILICON 24
SILICON ISOTOPES
SODIUM 20
SODIUM ISOTOPES
SPECTRA
SPECTROMETERS