Towards a He-buffered laser ablation ion source for collinear laser spectroscopy

Abstract

Laser ablation opens a material-independent method to produce ions from transition metals for laser spectroscopy. To overcome some drawbacks of this process, an ion source is under development at TU Darmstadt. A distinctive feature of this source is that ions are produced via laser ablation in presence of helium buffer gas where they stop and cool in the process of their collisions with the buffer gas atoms and are then extracted by the gas flow into low-pressure conditions through the supersonic nozzle. The compact RF-only funnel ion guide placed on the axis behind the nozzle exit allows for effective extraction of highquality ion beams into a pressure region below 10 −4 mbar. The extraction is realized by using the gas flow trough a supersonic nozzle and an RF-only funnel ion guide, followed by a second nozzle and an RF+DC funnel representing two differential pumping stages. The technical details of this laser ablation ion source are described and the results of the first tests with the RF-only funnel are presented.

Proposal of a New Double-Nozzle Technique for In-Gas-Jet Laser Resonance Ionization Spectroscopy

“…Note, that our calculation results (gas dynamic + Monte Carlo) for ions extracted from the gas jet into vacuum are in a good agreement with the measurements (see e.g. [43,44]). Based on our gas dynamic calculations, setups of gas-jet internal targets [49,50] have been created.…”

“…Similar computer simulations we were also making earlier for different ion beams cooling and bunching in helium buffer gas flows, and their results presented elsewhere (e.g. see [17][18][19][40][41][42][43][44][45][46][47][48]). Note, that our calculation results (gas dynamic + Monte Carlo) for ions extracted from the gas jet into vacuum are in a good agreement with the measurements (see e.g.…”

Proposal of a New Double-Nozzle Technique for In-Gas-Jet Laser Resonance Ionization Spectroscopy

“…Similar computer simulations were also made earlier for different ion beams cooling and bunching in helium buffer gas flows, and their results are presented elsewhere (e.g., see [17][18][19][40][41][42][43][44][45][46][47][48]). Note that our calculation results (gas dynamic + Monte Carlo) for ions extracted from the gas jet into a vacuum are in good agreement with the measurements (see, e.g., [43,44]). Based on our gas dynamic calculations, setups of gas-jet internal targets [49,50] have been created.…”

Review of Gas Dynamic RF-Only Funnel Technique for Low-Energy and High-Quality Ion Beam Extraction into a Vacuum

“…Moreover, it has been experimentally tested at Stanford University [ 29 , 30 ], ETH, Zürich [ 31 , 32 ], Technical University and Darmstadt [ 33 ]; currently, such extraction RF-only funnels are components of the facilities being developed at the Notre Dame University [ 34 , 35 ], McGill University, Montreal [ 36 ] and GSI, Darmstadt [ 37 ].…”

“…We proposed the third design variant of a laser ablation ion beam source in 2016 [ 42 ]. Later this proposal was realized at the Technical University (TU), Darmstadt as a prototype of a “He-buffered laser ablation ion source for collinear laser spectroscopy” [ 33 ] and it will also be used at the LASPEC experiment at FAIR [ 44 ].…”