Precise half-life measurement of the superallowed β+ emitter 10C
The half-life of '°C has been measured to be 19.310(4) s, a result with 0.02% precision, which is a factor of three improvement over the best previous result. Since 10 C is the lightest superallowed 0 + → 0 + β + emitter, its ft value has the greatest weight in setting an upper limit on the possible presence of scalar currents.
MARS: A momentum achromat recoil spectrometer
Abstract We are building a Momentum Achromat Recoil Spectrometer (MARS) for use with the new K500 superconducting cyclotron at Texas A&M University. MARS uses a unique optical design utilizing two dispersive planes to combine a momentum achromat with a recoil mass spectrometer. This configuration makes MARS applicable to a broad range of nuclear reaction studies utilizing inverse kinematics. It also leads to a system that is well matched to the range of secondary particle energies that will be produced in reactions with K500 beams. MARS will have a typical mass resolution of δM M ≅ 1 300 , with an energy acceptance of ± 9% ΔE E and a geometric solid angle of up to 9 msr. A beam swinger system will allow reaction products in the angular range 0° to 30° to be studied. MARS will be used to study both the excited states and decay properties of very proton- and neutron-rich nuclei. MARS will also be used to provide a reaction mechanism filter to assist investigations of the dynamics of heavy ion collisions and to produce secondary radioactive beams for reaction and spectroscopic studies of particular interest for nuclear astrophysics. We describe the design of MARS, together with a brief discussion of the scientific program planned for it.
Magnetic plasma confinement for laser ion source.
A laser ion source (LIS) can easily provide a high current beam. However, it has been difficult to obtain a longer beam pulse while keeping a high current. On occasion, longer beam pulses are required by certain applications. For example, more than 10 micros of beam pulse is required for injecting highly charged beams to a large sized synchrotron. To extend beam pulse width, a solenoid field was applied at the drift space of the LIS at Brookhaven National Laboratory. The solenoid field suppressed the diverging angle of the expanding plasma and the beam pulse was widened. Also, it was observed that the plasma state was conserved after passing through a few hundred gauss of the 480 mm length solenoid field.