Upload
others
View
1
Download
0
Embed Size (px)
Citation preview
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