A field programmable gate array-based time-resolved scaler for collinear laser spectroscopy with bunched radioactive potassium beams.

A new data acquisition system including a Field Programmable Gate Array (FPGA) based time-resolved scaler was developed for laser-induced fluorescence and beam bunch coincidence measurements. The FPGA scaler was tested in a collinear laser-spectroscopy experiment on radioactive K-37 at the BEam COoler and LAser spectroscopy (BECOLA) facility at the National Superconducting Cyclotron Laboratory at Michigan State University. A 1.29 mu s bunch width from the buncher and a bunch repetition rate of 2.5 Hz led to a background suppression factor of 3.1 x 10(5) in resonant photon detection measurements. The hyperfine structure of K-37 and its isotope shift relative to the stable K-39 were determined using 5 x 10(4) s(-1) K-37 ions injected into the BECOLA beam line. The obtained hyperfine coupling constants A(S-2(1/2)) = 120.3(1.4) MHz, A(P-2(1/2)) = 15.2(1.1) MHz, and A(P-2(3/2)) = 1.4(8) MHz, and the isotope shift delta nu(39, 37) = -264(3) MHz are consistent with the previously determined values, where available. (c) 2014 AIP Publishing LLC.