Towards sympathetic cooling of trapped ions with laser-Towards sympathetic cooling of trapped ions with laser-cooled Mg+ ions for mass spectrometry and laser cooled Mg+ ions for mass spectrometry and laser
spectroscopyspectroscopy
Radu Cazan
The PurposeThe Purpose
Setup of a system for cooling ions in a trap to a very low temperature,regardless of their
- charge state,- energy level structure or - other parameters
-> sympathetic cooling by laser cooled Mg ions.
M. Bussmann, Int.J.MassSpec. 251, 179(2006)
Cooling technique Limit Temperature (typ.) Cooling Time
Resistive Cooling ~ 4 K > 1 s
Buffer Gas Cooling ~ 4 K ~10 – 100 ms
Electron Cooling < 1 K ~100 ms – 1 s
Laser Cooling ~ 1 – 10 mK (ħΓ/2kB) ~ 1 ms
Sympathetic Cooling < 0.25 K ~ 1 ms
Sisyphus Cooling ~ μK ~ 1 ms
An overview of cooling techniquesAn overview of cooling techniques
First resonatorFirst resonator
for P1118=970 mW
~775 mW coupled
P559=325 mW
Enhancement factor A~40-60
First resonatorFirst resonator- resized & refurbished laser- resized & refurbished laser
for P1118~1050 mW
?% ASE & 2nd mode
P559=170-210 mW
P=1.85 W intwo modes +0.45 W A.S.E.
Maximum c.e.~57%
=>P1118~600 mW
Smaller cavity:
+ increased FSR =
+ increased bandwidth
+ better stability
- up to 10% less output in our case
Second resonatorSecond resonator
P279=16.7 mW max
~15 mW average
for P559~210 mW
~170 mW coupled
Enhancement factor A~60-70