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Characterizing the EBIS-C Spectrometer. Leah VanNahmen REU 2006 Kansas State University. Introduction. Spectrometer Basics Recoil Ions Beam Fragments Summary Applications. Spectrometer Basics. GOAL: Determine initial momentum of all products from a collision Gas Jet = Recoil Ions
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Characterizing the EBIS-C Spectrometer Leah VanNahmen REU 2006 Kansas State University
Introduction • Spectrometer Basics • Recoil Ions • Beam Fragments • Summary • Applications
Spectrometer Basics • GOAL: Determine initial momentum of all products from a collision • Gas Jet = Recoil Ions • Particle Beam = Beam Fragments • Detector MCP and PSD collect TOF and Final Position
Recoil Ions • We find recoil ions’ initial momentum from TOF using momentum conversion • Problem: Particles with different initial momenta can have the same TOF
Recoil Ions Solution: Space and Time Focusing • Make “voltage hill” • Best focusing if 2nd applied voltage is 82.8% of 1st voltage
The EBIS-C spectrometer has great focusing! Recoil Ions
Magnification of Y Position Magnification of Y Velocity Beam Fragments Problem: Magnification D = vt Spectrometer Axis Spectrometer Axis
Beam Fragments Solution: Find an equation to correct for both kinds of magnification
Beam Fragments Overall Magnification Solution: • Overall magnified Y position =magnification of Y positionxinitial y position+magnification of Y velocityxinitial Y velocityxTOF • Ym= MYix Yi+ MVyx vy x TOF
Summary • Apply two voltages to spectrometer to focus recoil ions • Correct for magnification of beam fragments • End up with enough equations to find the initial momentum of all the products from a collision
Applications • This characterization will allow experimenters to quickly and easily focus the EBIS-C spectrometer and correct for the magnification it causes • The spectrometer will be used in the EBIS-C beamline for future experiments…..
Applications In Ar/He experiment: Ar + H2+ • H+ + H + Ar • H + H + Ar+