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The TITAN-EBIT
(Electron Beam Ion Trap)
A Status ReportGünther Sikler
Introduction- Motivation- Principle
Setup- Requirements- Status
Outlook- Schedule- Measurements
NBqTm
mm
RF ⋅⋅⋅≈
δB
mq
c ⋅⋅=π
ν21
• High precision mass measurements
– Higher q (or B) allows for • better accuracy or
• shorter observation times or
• smaller count rate
EBIT meets rare isotope facilityMotivation
mmδ
RFT
N
• “EBIT physics”: Spectroscopy on HCI → Test QED– Calculations for heavier systems limited by
» applicability of perturbation theory» nuclear effects
→ J. Braun (this workshop)
The electron beam is compressed by a magnetic (Helmholtz) field.
Ions are trappedradially by space charge potential, longitudinally by external field.
Creation of highly charged ionsby multiple subsequent electron impact
The principle of an EBIT
Be- beam
B ≈ 6 - 8 T,Ie ≈ 0.1 – 1 Adeb ≈ 100µm,φsc ≈ 0.1 – 1 keVTion ≈ 100 – 500 eVtionize ≈ 1 ms – 10 s
Charge breeding of RadionuclidesCharge breeding of Radionuclides
Charge state (10 Charge state (10 –– 50)50)‘medium’ high voltage;‘medium’ high voltage; design value: design value: E = 20keVE = 20keV
RapidRapid charge breeding (5 charge breeding (5 –– 50 ms)50 ms)High electron current; design value: High electron current; design value: I = 5 AI = 5 A
Injection + ExtractionInjection + Extraction with high efficiencyopen apertures + open apertures + improved ion opticsimproved ion optics
Handling Handling isobaric contaminationsisobaric contaminationslarge trap, deep space charge potentialslarge trap, deep space charge potentials
..
..
..
Further RequirementsFurther RequirementsCapture into a Penning trap
injection into a strong magnetic field(more critical for HCIs)
deceleration to restshort bunches, small emittance, small ∆E
Extraction of ions in well-defined charge statedriving the cyclotron frequency of the desired speciesextraction over an electrostatic barrierradially segmented central trap electrode extraction\ injection path covered with electrodes
pump
pump
pump
manipulator
insulators
shutter valve
magnet
collector
compensator
insulators
trap
electrongun
ElectronGun
Cathode assembly
Collector
21 mm
174 mm
(provisional)Trap
Outlook:
June ’05: first electron beam (I<500mA, E<2keV)first extraction of ions (injected as neutrals)
July ’05: advanced tests of injection/extraction opticsfirst injection of ions (from test ion source)
-Sept. ’05: final trap setup ready for operationlast installations (electric, cooling..) complete
creeping out of the valley of tears
q/m selection, pos. sensitive detector, emittance meter, TOF-detection, etc…
in operation
Measurement Program:
optimize electron beam current, energy spread
optimize injection and stopping
investigate cooling by admixture of ‘light’ gascharge selective extraction
check characteristics: bunch-length
breeding time charge state
Ie Ee
energy spreademittance
J. Crespo, J. Dilling, S. Epp, M. Froese, G. Sikler, J. Ullrichand the HD-EBIT groupC. Osborne, M. Trinczek
