1 Evaporative Cooling of Ions in Linear Paul

Overview 2 What we are trying to achieve Theory Results Discussion Where to go

Goals & Motivation 3 Evaporative cooling in Linear Paul traps Cooling method independent of

Evaporative Cooling #particles 4 #particles Energy

Evaporative Cooling 6 Particles must interact, and allow system to equilibrate Highest energy particles

Electrode Configuration Shape of the potential at some to and half a period later

Ions in Linear Paul Traps 8 Simple harmonic motion in z-direction Number of particles

Radial Potential Reduction Rate Axial Potential Reduction Rate 9

Method of Investigation 10 a and q are systematically picked RPRR and APRR are

Conclusion 14 Evaporative cooling overcomes intrinsic heating of LPT Evaporative cooling can be optimized

Future work 15 Run MC sets for lower q values to verify interaction rate

Results 16 Temperature drops of min ~ -1 K/Particle max ~ 120 K/Particle Unsuccessful

Constants 17 Initial particles = 256 Initial temperature = 450 K Simulation time of

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1 Evaporative Cooling of Ions in Linear Paul Traps LOHRASP SEIFY UNDER THE SUPERVISION OF DR. ROBERT THOMPSON

Overview 2 What we are trying to achieve Theory Results Discussion Where to go from here 2

Goals & Motivation 3 Evaporative cooling in Linear Paul traps Cooling method independent of species Non-invasive, universal method of cooling Titan trap mass measurement Optimize temperature drop per particle lost 3

Evaporative Cooling #particles 4 #particles Energy

Evaporative Cooling 5 5

Evaporative Cooling 6 Particles must interact, and allow system to equilibrate Highest energy particles are allowed to escape 6

Electrode Configuration Shape of the potential at some to and half a period later Ω : Oscillation Frequency ro : Radius of the trap zo : Length of the trap UDC : Amplitude of DC component UAC : Amplitude of AC component Images from: 7 Humboldt-Universität zu Berlin - http: //www. physik. hu-berlin. de/nano/forschung-en/np

Ions in Linear Paul Traps 8 Simple harmonic motion in z-direction Number of particles and energy not conserved Particle-trap heating Particle-particle coulomb heating Any cooling method must compete with above 8

Radial Potential Reduction Rate Axial Potential Reduction Rate 9

Method of Investigation 10 a and q are systematically picked RPRR and APRR are picked by monte-carlo method Simulations model the ensemble Cooling measured 10

Results 11 11

Results 12 12

Results 13 13

Conclusion 14 Evaporative cooling overcomes intrinsic heating of LPT Evaporative cooling can be optimized Temperature drop of ~95% , by losing less than 10% of initial particles 14

Future work 15 Run MC sets for lower q values to verify interaction rate Apply evaporative cooling to experiments in TITAN located in TRIUMF 15

Results 16 Temperature drops of min ~ -1 K/Particle max ~ 120 K/Particle Unsuccessful runs: A lot of heating before good evaporations A lot of heating, and only bad evaporations 16

Constants 17 Initial particles = 256 Initial temperature = 450 K Simulation time of 5 x 10 -4 sec Computational time of ~4 hours 17

Not all data is useful 18

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