Speaker
Description
Recently, the collinear laser spectroscopy (CLS) apparatus, called CLaSsy, has been successfully commissioned, which has been tested by using the Na isotopes from the ISOL facility at RAON. The spectroscopic resolution achieved has been sufficient to resolve the D1 line hyperfine structure of the $^2$S$_{1/2}$ ground state and the $^2$P$_{1/2}$ excited state, while limiting the measurement of the hyperfine splitting of the $^2$P$_{3/2}$ state in the transition of the D2 line. For the precise measurements of nuclear magnetic and quadrupole moments, the spectroscopic resolution requires resolving hyperfine structure splitting below 100 MHz regime, which is ultimately limited by Doppler broadening. In the conventional collinear laser spectroscopy, the kinematic compression of Doppler-broadening effects provides the spectroscopic resolution down to experimental linewidths of about 100 MHz, which is limited by the beam energy and the energy spread of the CW/bunched ion beam sent to the CLS beamline.
The combination of collinear and anti-collinear geometry offers additional benefits that allow the high precision measurement by the ion beam energy calibration and high-resolution laser spectroscopy close to the natural linewidth of the transition. Since the accelerated ion/atom beam is overlapped with the laser beam, optical resonance occurs when the Doppler shifted laser frequency depending on the collinear and anti-collinear geometry is tuned to the atomic resonance frequency. By comparing the spectroscopic signals from the different geometry, the ion beam energy can be calibrated, which allows precise measurement of the isotope shift. On the other hand, high-resolution Doppler-free laser spectroscopic measurement can be achievable when the two laser beams from different geometry are used together at the same time, by selecting the velocity group contributing to the ion/atom-light interaction. Here, we will present this proposed technique for high-resolution laser spectroscopy in the CLS beamline as well as future experimental plans.
| Email address | sjpark@ibs.re.kr |
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| Classification | Instrumentation for radioactive ion beam experiments |
