Speaker
Description
Laser spectroscopy and ionization are already well established tools for the analysis or production of radioactive ion beams. However, to best suit the needs of specific applications, new or modified laser systems are required. We present our recent progress and several applications of these new systems.
Two-photon transitions require high pulse energy and short pulse duration for efficient excitation. A simple approach for generation of such pulses is the use of a reduced laser cavity length. A 3.5cm Ti:sa laser cavity with a two-prism tuner for wavelength selection is demonstrated. Pulses of $>$ 1mJ energy with pulse durations below 3$\,$ns at 905nm were produced using an old flashlamp-pumped YAG laser as pump source. In a recent experiment (2018) at the J-PARC facility the system was used for fluorescence studies in He$_2$$^*$ excimer clusters, which were generated by recoils of the neutron induced $^3$He(n,p)$^3$T reaction[1]. The fluorescence from these clusters may in the future allow 3D particle tracking velocimetry to investigate the superfluid phase in liquid helium.
Multi-element studies require either multiple expensive laser systems or the ability to quickly switch the wavelength of the laser system from one element of interest to another. A widely-tunable grating Ti:sapphire laser system with intra-cavity frequency doubling and motorized wavelength selection was developed. The system was applied to Secondary Neutral Mass Spectrometry (SNMS)[2] of Zr and Cs.
High resolution resonance ionization spectroscopy for the analysis of isotope shifts and hyperfine structure is possible with an injection-locked Ti:sapphire laser [3]. For increased wavelength flexibility we have started development of a continuous-wave direct diode pumped Ti:sapphire (DDPTS) laser to be used as master-laser source for generating the seed radiation. The use of inexpensive diodes as compared to frequency doubled YAG lasers as pump source will make this solution very cost-efficient.
[1] W. Guo et al., J. Instrum.(2012) 7 01 P01002
[2] T. Sakamoto (2018) Laser Ionization SNMS. In: Compendium of Surface and Interface Analysis. Springer, Singapore
[3] V. Sonnenschein et al. Las. Phys., (2017), 27(8):085701