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)

http://www.kernchemie.uni-mainz.de/

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

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

Second resonatorSecond resonator

P279=16.7 mW max

~15 mW average

for P559~210 mW

~170 mW coupled

Enhancement factor A~60-70