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Studying Exotic IsotopesDetermine nuclear properties by observing HFS via collinear laser spectroscopy.
Currently in the process of studying manganese.
Possible to study chromium using similar method:
Focussing on Anomalous Region
Mn and adjacent isotope chains do not show ‘kink’ in 2-neutron separation energies.
However the change in nuclear mean-squared radius shows expected contraction:
New Cyclotron and BeamlineNew cyclotron is dedicated to IGISOL line.Beam-line is being rebuilt and upgraded.
Forward Doppler ContractionAccelerated Beams reduces Doppler broadening down to natural
widths:
Cooled ions means slower beams can be used.
However Cooler-Buncher is set at high voltage to receive high energy ions from the IGISOL.
Deceleration RegionCEC placed inside: Neutralisation means transitions are less energetic.Combine with HV box for state-selective charge exchange:
High voltage region insulated by 25% glass filled PTFE pipe segments.
HV platform to decelerate ions: Increased pumping time and time in LCR.
Mini-RFQ trapMini-RFQ trap placed inside:
Storage: Bunching and pumping.Photo-chemistry to remove contaminants.
Hf+ + O2 HfO+
“Elevator” to change ion energy.Traps passing ions between them to build up ions.
Beam TrajectoryNew beam-line means new beam trajectory needs to be calculated.Beam-line built using existing components; possible problems.Using ion optics simulator SIMION®.
User programs:changing potentials (eg: RFQ)charge-exchangerandomise initial ion conditionsetc...
SIMION is being used to optimise transmission through the beam-line and to indicate any possible problems.
Existing line at ISOLDE modelled and highlights known issues.
Possible Problems I
Minor problems: Parallel plates block beam.Solution: Simple adjustment of apparatus.
Possible Problems IIMajor problems: Fringe fields causing the ion beam to misalign.
Solutions: New apparatus such as parallel plates and quadrupole doublet.
The Future
New Lab is under construction.Dedicated cyclotron.Upgraded beam-line.
Upgrades will allow study of previously unavailable isotopes and give greater flexibility to the beam-line.Decelerated beams.State-selective charge exchange.Secondary trap.
New beam trajectory needs to be calculated and optimised using SIMION, and any indicated problems dealt with.
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