Decay studies of nuclei near the proton drip line: /sup 35/Ca, /sup 31/Ar, /sup 69/Br, /sup 65/As

Technical Report · Thu Jun 01 04:00:00 EDT 1989

DOI:https://doi.org/10.2172/5918746· OSTI ID:5918746

Reiff, J E

Studies of new beta-delayed two-proton emitters and a search for ground state proton radioactivity in medium mass nuclei were performed using various experimental techniques in conjunction with several detection systems. A helium-jet transport system and three-element silicon telescopes were used to discover the existence and detect the decay of the first T/sub Z/ = /minus/5/2 nuclide, /sup 35/Ca. Two-proton emission from the T = 5/2 isobaric analog state in /sup 35/K at an excitation energy of 9.053 /plus minus/ 0.045 MeV, fed by the superallowed beta decay of /sup 35/Ca, resulted in transitions to both the ground state and first excited state of /sup 33/Cl. The corresponding two-proton sum energies were 4.089 /plus minus/ 0.030 MeV and 3.287 /plus minus/ 0.030 MeV. Measurements of the individual proton energies indicated the prevalence of a sequential decay mechanism. Using the isobaric multiplet mass equation, the mass excess of /sup 35/Ca was calculated to be 4.453 /plus minus/ 0.060 MeV. In order to study whose half-lives were too short for the helium-jet system, an in-beam recoil catcher wheel was constructed. The wheel speed can be varied to study nuclides whose half-lives range from 100 /mu/s to /approximately/250 ms. The first new decay observed with the wheel system and traditional /Delta/E-E telescopes was the beta-delayed two-proton emission from /sup 31/Ar. The two-proton sum energy of /approximately/7.5 MeV corresponds to a transition from the isobaric analog state in /sup 31/Cl to the ground state of /sup 29/P. The search for proton radioactivity required the development of low energy, particle identification detector telescopes. These telescopes, comprised of a gas /Delta/E and silicon E, were used in conjunction with the in-beam recoil catcher wheel to search for ground state proton emission from /sup 69/Br and /sup 65/As. 90 refs., 24 figs., 8 tabs.

• Research Organization: Lawrence Berkeley Lab., CA (USA)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 5918746
• Report Number(s): LBL-27387; ON: DE89015342
• Country of Publication: United States
• Language: English

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73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ALKALINE EARTH ISOTOPES
AMPLITUDES
ARGON 31
ARGON ISOTOPES
ARSENIC 66
ARSENIC ISOTOPES
BETA DECAY
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
BROMINE 69
BROMINE ISOTOPES
CALCIUM 35
CALCIUM ISOTOPES
DATA ACQUISITION SYSTEMS
DECAY
DETECTION
EVEN-ODD NUCLEI
INTERMEDIATE MASS NUCLEI
ISOTOPES
LIGHT NUCLEI
MILLISEC LIVING RADIOISOTOPES
NUCLEAR DECAY
NUCLEI
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
RADIOISOTOPES
TRANSITION AMPLITUDES