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| Near-infrared picture of a fluorescing cloud of Cs atoms trapped
in a MOT. |
The atom trapping team at
Los Alamos has developed an efficient method of trapping radioactive
atoms for both fundamental and applied research. This project makes
use of advances in atomic physics that allows us to cool,
trap and manipulate neutral atoms.
Our system
uses a high-efficiency magneto-optical trap (MOT) that is coupled to
an off-line mass separator. Once the desired atoms are trapped they
can be detected with high sensitivity or transferred to another trap
where a variety of experiments are performed. We are presently pursuing
the following research areas:
1. Parity
violation in
beta-decay
We have recently demonstrated the trapping of polarized 82Rb (t1/2=75
s) to observe the parity-violating beta-nuclear spin correlation (setup
and data). A 1% measurement of this correlation is planned to further
test the maximal parity violating nature of the weak interaction and
to search for new physics beyond the Standard
Model.
2. Ultrasensitive detection
For nonproliferation and environmental/dating applications, we are using
the high selectivity and sensitivity of the mass separator–MOT
system to detect small numbers of selected radioisotopes. To date we
have trapped 135Cs (t1/2=2 x 10^6 y) and 137Cs (t1/2=30 y) and measured
their isotopic ratio for the first time in a MOT with sensitivities
as small as 10^7 atoms per sample.
3. Ultracold atoms / quantum
degenerate matter
The ability to trap and cool different isotopes (both radioactive and
stable) enables us to explore mixed fermionic
and bosonic systems. In particular, we are working to produce a
Bose-Einstein
condensate of 87Rb and overlap it with a magnetically trapped cloud
of fermionic 84Rb (t1/2=33 d) to investigate cold inter-isotopic collisions,
explore sympathetic (i.e., collisional) cooling, and produce/study Fermi
degenerate matter.
