High-B - University of Michigan

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Transcript High-B - University of Michigan

Modification to Various Projects
in Raithel’s Lab
Louise Niu, University of Michigan REU 2008
Advisor: Georg Raithel
http://cold-atoms.physics.lsa.umich.edu
Outline
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Magneto-Optical Trap
• Laser Cooling & MOT
• Building Compensating Magnetic Coils
Bose-Einstein Condensation
• How to make a BEC
• Building High Voltage Power Supply
Laser Cooling
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Rb Atoms absorb photons in the laser beam
Conservation of Momentum
Atom slows down
Atom spits photons in a random direction
Continuous photon stream from one direction
One dimensional laser cooling Animation
Atom
Magneto-Optical Trap (MOT)
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3 orthogonal pairs of counterpropagating laser beams.
Quadruple magnetic field trap
atoms in the center.
Cool Rb Atoms to 1mK. (MOT)
Building Compensating Magnetic Coils
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Motivation:
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Create bias magnetic field to adjust MOT postion for Cryo-MOT
Design & Setup:
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3-dimentional Anti-Helmholtz magnetic field
Each pair coils generates 2 gauss magnetic field in its center
Vertical direction: wrap coils on the chamber
Horizontal plane: coil form+cardboard
Made by Louise !! lol
Building Compensating Magnetic Coils
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MATLAB Simulation:
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Building Compensating Magnetic Coils
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1. Coil Wrapping
2. Mount Coils
3.Connect to Power Supply
Testing
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Building Compensating Magnetic Coils
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Bose-Einstein Condensation (BEC)
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Bosonic Atoms: having integer spin
Low temperature: very close to absolute zero (10s of nK)
Atoms are in the same lowest energy level
Atoms are absolutely identical
Act as one giant wave
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How to make a BEC
1. Laser cooling and trapping
2. Turn laser light off and turn 3-D
magnetic trap on
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3. Evaporative cooling:
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Building High Voltage Power Supply
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Motivation:
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To supply high voltage for MCP
Micro-Channel Plate:
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A component to detect Ions
Phosphor screen
Ions
Phosphor screen
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Building High Voltage Power Supply
Power supply
High V-source
Current meter
Power switch
Aluminum Box
Power plug
Building High Voltage Power Supply
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In addition…
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Other projects:
 Laser
Amplifier
 Pulsed Coil
 Atom Laser
 Software Applied:
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MATLAB
Mathematica
Photoshop
Adobe Illustrator
AutoCAD
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Acknowledgements
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Prof. Georg Raithel
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Graduate Students:
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Aaron Reinhard
Brenton Knuffman
Eric Paradis
Kelly Younge
Mallory Traxler
Melinda Morang
Rachel Sapiro
Rahul Mhaskar
Rui Zhang
Undergraduate Students:
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Jordan Montgomery
Varun Vaidya
Thanks for your attention !