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CPOTS 2013: 3 rd ERASMUS IP on Charge Particle Optics – Theory and Simulation Dept. of Physics, University of Crete, Heraklion, GREECE Project Coordinator: Prof. Theo Zouros (tzouros@physics.uoc.gr) CPOTS – 2 nd ERASMUS Intensive Program Introduction to Charged Particle Optics: Theory and Simulation http://cpots2012.physics.uoc.gr Dept. of Physics, University of Crete Aug 19 – Sept 2, 2012 Heraklion, Crete, GREECE
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http://cpots2012.physics.uoc.gr 2 Group Project Magnetic Bottle Electron Spectrometer Nimet Okumuş Socrates Anastasopoulos David Alcocer Velarde
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3 Abstract The principles of magnetic bottle mass spectrometer Theoretical analysis Energy resolution of magnetic bottle spectrometer Conclusions
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4 Magnetic Bottle Electron Spectrometer Electrons spiral in B field which reduces adiabatically Electron energy measured by time of flight to detector Lets use a standard spectrometer, e.g. hemispherical analyser with an entrance aperture Very small solid angle, most electrons lost! 4 collection of electrons Weak uniform B field Strong B field The use of permanent magnets requires modifications of the transition region (between the high-field electron production zone and the low-field drift tube analyzer) to avoid axial field reversals associated with fringing fields. e-e- e-e- e-e- e-e- Analyser
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5 Investigate Spectrometer Properties Measure the time of flight for electrons with different conditions (using Record function) Find the energy resolution of the spectrometer in different situation
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SIMION Magnetic Bottle Spectrometer Particles Definition
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SIMION Magnetic Bottle Spectrometer Flying Particles Three different group with energy 40, 20, 5 eV
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8 S IMION Modelling of Magnetic Bottle Spectrometer Energy Resolution of Spectrometer K is constant. From this 2 equations we exported the relation between Kinetic Energy and TOF
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SIMION Magnetic Bottle Spectrometer B i =2000 gauss B f =10 gauss Transition Region=9 mm K=0.179574 eV µsec² Calibration factor=KE×(TOF) 2
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Convertion TOF to KE TOF KE
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Magnetic Bottle Spectrometer Resolution The resolution of the Spectrometer is: 10%
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CPOTS 2012: S9 - JBG http://cpots2012.physics.uoc.gr 12/XX ΔKE Energy resolution = 19.75 eV/(20.6-18.6) eV ≈10% ΔKE Energy resolution = 9.95 eV/(10.4-9.4) eV ≈ 10% Energy resolution doesn’t depend on KE.
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CPOTS 2012: S9 - JBG http://cpots2012.physics.uoc.gr 13/XX Resolution= 9.6 / (10.35-8.9)=6.6% B i = 3000 Gauss ΔKE B i =8000 Gauss ΔKE Resolution= 8.6/ (10.25-7.1)=2.7% Resolution
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CPOTS 2012: S9 - JBG http://cpots2012.physics.uoc.gr 14/XX Conclusion Resolution of spectrometer is depent on length of the time of flight tube. The resolution changes with B field. Energy resolution doesn’t depend on KE.
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