Magnetic Injection Scheme for The Atom Laser
Transcript of Magnetic Injection Scheme for The Atom Laser
Magnetic Injection Scheme for The Atom Laser
Karl LundquistREU Summer 2010
Raithel LabAugust 17 2010
Outline
• Overview of current generation atom laser setup
• Theory/Simulation of magnetic injection• Experimental setup of magnetic injection
o In the vacuum oElectronicsoEnclosureoSoftware
Overview of current setup
• Zeeman slower• Primary MOT• Pusher Beam• Secondary MOT• Magnetic Injection• Magnetic Compression• Surface Adsorption
evaporative cooling• Continuous BEC!
Basic idea behind magnetic injection
• Transferring atom into evaporative cooling region with light would cause atoms to gain heat.
• Instead, if we transfer atoms with magnetic field only, the process can be slow enough to be adiabatic.
• From secondary MOT, we can transfer atoms along the guide using a moving magnetic field minimum.
Magnetic field sources in the injection region
• Guiding wires produce transverse trapping potential (~250 amps)
• Injection coils produce moving magnetic field minimum (2-3 amps each)
• Racetrack coils produce quadrupole magnetic field for secondary MOT
High Current Power Supply
• HP6651A• 0-8 Volts• 0-50 Amps• Low gauge wire and
aluminum rods for high current transport
Circuit setup• Need easy way to control
current in each coil with low voltage signal from computer
• Traditional differential amplifier setup
• Must drop signal over R test in order to maintain equilibrium
• op-amp pushes transistor base until allowed current causes required voltage drop
• R=.5 Ohms• I=V/R => I = 2V*(1/Ohm)• Directly proportional
Testing
• Measuring voltage across load resistor will indicate the amount of current flowing through coils
• A circuit can be tested by checking that the signal in is identical to the signal out
Cooling
• 2-3 Amps through transistors makes them very hot
• use heat sinks and high powered fans too keep them cool
Circuit Control• United Electronics
Industries PowerDNA Cube
• Allows for DAQ communication via Ethernet port
• LabVIEW userinterface