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RESEARCH PRODUCT

Gas jet studies towards an optimization of the IGISOL LIST method

B. A. MarshJ. KurpetaT. KesslerM. ReponenVolker SonnenscheinIlkka PohjalainenJuha ÄYstöPasi KarvonenS. PiszczekIain Moore

subject

Overall pressure ratioPhysicsNuclear and High Energy PhysicsJet (fluid)Argonta114Expansion chamberAstrophysics::High Energy Astrophysical PhenomenaNozzlechemistry.chemical_elementPitot tubeIon sourcelaw.inventionchemistrylawAtomic physicsInstrumentationHelium

description

Abstract Gas jets emitted from an ion guide have been studied as a function of nozzle type and gas cell-to-background pressure ratio in order to obtain a low divergent, uniform jet over a distance of several cm. The jet has been probed by imaging the light emitted from excited argon or helium gas atoms. For a simple exit hole or converging-diverging nozzle, the jet diameter was found to be insensitive to the nozzle shape and inlet pressure. Sonic jets with a FWHM below 6 mm were achieved with a background pressure larger than 1 mbar in the expansion chamber. The measurements are supported by the detection of radioactive 219 Rn recoils from an alpha recoil source mounted within the gas cell. A Laval nozzle produced a well-collimated supersonic jet at low background pressures with a FWHM of ∼ 6 mm over a distance of 14 cm. Direct Pitot probe measurements, on-axis, revealed a non-uniform pressure distribution in the gas jet of the Laval nozzle, supporting the visual observations. All measurements are motivated by the requirement of a good geometrical overlap between atoms and counter-propagating laser beams in the gas cell-based Laser Ion Source Trap (LIST) project. Computational fluid dynamics gas flow simulations were initiated to guide the future development of the gas jet system.

yearjournalcountryeditionlanguage
2011-04-01Nuclear Instruments and Methods in Physics Research Section A
10.1016/j.nima.2011.01.125https://doi.org/10.1016/j.nima.2011.01.125