[en] For the on-line production of a ¹⁴O⁺ ion beam, an integrated target--transfer line ion source system is now under development at LBNL. ¹⁴O is produced in the form of CO in a high temperature carbon target using a 20 MeV ³He beam from the LBNL 88'' Cyclotron via the reaction ¹²C(³He,n)¹⁴O. The neutral radioactive CO molecules diffuse through an 8 m room temperature stainless steel line from the target chamber into a cusp ion source. The molecules are dissociated, ionized and extracted at energies of 20 to 30 keV and mass separated with a double focusing bending magnet. The different components of the setup are described. The release and transport efficiency for the CO molecules from the target through the transfer line was measured for various target temperatures. The ion beam transport efficiencies and the off-line ion source efficiencies for Ar, O₂ and CO are presented. Ionization efficiencies of 28% for Ar⁺, 1% for CO, 0.7% for O⁺, 0.33 for C⁺ have been measured

No abstract available

[en] For the on-line production of a ¹⁴O⁺ ion beam, an integrated target transfer line ion source system is now under development at LBNL. ¹⁴O is produced in the form of CO in a high temperature carbon target using a 20 MeV ³He beam from the LBNL 88^double-prime Cyclotron via the reaction ¹²C(³He,n)¹⁴O. The neutral radioactive CO molecules diffuse through an 8 m room temperature stainless steel line from the target chamber into a cusp ion source. The molecules are dissociated, ionized and extracted at energies of 20 to 30 keV and mass separated with a double focusing bending magnet. The different components of the setup are described. The release and transport efficiency for the CO molecules from the target through the transfer line was measured for various target temperatures. The ion beam transport efficiencies and the off-line ion source efficiencies for Ar, O₂ and CO are presented. Ionization efficiencies of 28% for Ar⁺, 1% for CO, 0.7% for O⁺, 0.33 for C⁺ have been measured. copyright 1999 American Institute of Physics

[en] For the on-line production of a ¹⁴O⁺ ion beam, an integrated target-transfer line ion source system is now under development at LBNL. ¹⁴O is produced in the form of CO in a high temperature carbon target using a 20 MeV ³He beam from the LBNL 88'' Cyclotron via the reaction ¹²C(³He,n)¹⁴O. The neutral radioactive CO molecules diffuse through an 8 m room temperature stainless steel line from the target chamber into a cusp ion source. The molecules are dissociated, ionized and extracted at energies of 20 to 30 keV and mass separated with a double focusing bending magnet. The different components of the setup are described. The release and transport efficiency for the CO molecules from the target through the transfer line was measured for various target temperatures. The ion beam transport efficiencies and the off-line ion source efficiencies for Ar, O₂ and CO are presented. Ionization efficiencies of 28% for Ar⁺, 1% for CO, 0.7% for O⁺, 0.33 for C⁺ have been measured

[en] We have measured the β-γ directional correlation coefficient A₂₂ in the decay of ²²Na to the 2⁺ 1275 keV excited state of ²²Ne. We find A₂₂=(5.3±2.5)x10^-4. This measurement has higher precision but disagrees with most previous experiments. The value for A₂₂, combined with other experimental inputs, gives recoil-order form factors in disagreement with theoretical estimates. This experiment demonstrates the capabilities of Gammasphere as an instrument for precise β-γ correlation measurements. copyright 1999 The American Physical Society

[en] The charge-state distribution following the β⁺ decay of²¹Na has been measured, showing a larger than expected fraction of the daughter ²¹Ne in positive charge states. No dependence on either the β⁺ or recoil nucleus energy is observed. The data are compared to a simple model based on the sudden approximation. Calculations suggest that a small but important contribution from recoil ionization has significant consequences for precision β decay correlation experiments detecting recoil ions

[en] We have measured the half-life of ¹⁴O, a superallowed (0⁺→0⁺) β decay isotope. The ¹⁴O was produced by the ¹²C(³He,n)¹⁴O reaction using a carbon aerogel target. A low-energy ion beam of ¹⁴O was mass separated and implanted in a thin beryllium foil. The beta particles were counted with plastic scintillator detectors. We find t_1/2=70.696±0.052 s. This result is 1.5σ higher than an average value from six earlier experiments, but agrees more closely with the most recent previous measurement

No abstract available

No abstract available

[en] A prototype of a solid deuterium (SD₂) source of Ultra-Cold Neutrons (UCN) is currently being tested at LANSCE. The source is contained within an assembly consisting of a 4 K polyethylene moderator surrounded by a 77 K beryllium flux trap in which is embedded a spallation target. Time-of-flight measurements have been made of the cold neutron spectrum emerging directly from the flux trap assembly. A comparison is presented of these measurements with results of Monte Carlo (LAHET/MCNP) calculations of the cold neutron fluxes produced in the prototype assembly by a beam of 800 MeV protons incident on the tungsten target. A UCN detector was coupled to the assembly through a guide system with a critical velocity of 8 m/s (⁵⁸Ni). The rates and time-of-flight data from this detector are compared with calculated values. Measurements of UCN production as a function of SD₂ volume (thickness) are compared with predicted values. The dependence of UCN production on SD₂ temperature and proton beam intensity are also presented