TRIX: Trapped Radium Ion eXperiments
Oscar Versolato
TRImP: Trapped Radioactive Isotopes: micro-laboratories for fundamental Physics
Outline
• Where’s The Netherlands in Amsterdam?
• Introduction to research group TRImP
• TRIX project: Trapped (single !) Radium Ion eXperiments
• Bonus material 1: shelving
• Bonus material 2: ion trapping
Kingdom of The Netherlands
Where people are Dutch and from Holland
To US
Er gaat niets boven Groningen
Groningen: a students dream come true
However...
Accelerator Laboratory: KVI
with superconducting cyclotron AGOR
TRImP:
Trapped Radioactive Isotopes: micro-laboratories
for fundamental Physics
Motivation
Low-energy tests of the Standard Model
The Standard Model (SM) of particle physics is incomplete 
searches for physics “beyond the SM” at two, complementary, fronts:
Collider expt’s at high energy: direct
observation of new particles
Indirect searches at lower energies,
but with high precision
Large Hadron Collider
TRImP

CERN
High-energy physics
KVI
Atomic physics (theory
and experiment) < 1%
TRImP
TRImP: Trapped Radioactive Isotopes: micro-laboratories for fundamental Physics
Particle
Physics
Nuclear
Physics
TRImP
Atomic
Physics
Theory
Core
External
- lifetimes, CKM
- branching ratios
- 12C → 3a
- 8B → 2a
-…
Program
Users
App lications
Precision Experiments
Search for Physics beyond
Standard Model
T-violation
P-violation
Lorentz-violation
- Ion/Atom
Collisions
- Zernike LEIF
- ALCaTRAZ
- Instrument
Developments
-…
In-House Core Program
T – violation:
• b-decays
• 21Na
• EDMs
• Ba/Ra – atom
• trapping
• polarization
• deuteron
P – violation:
• Single Ion
• sin2 ϴW
• clock
Lorentz - violation:
• Weak Interactions
Countrate [106 /s]
• ‘a’ & ‘D’ coefficients
• lifetime, branching ratio
• Future Possibilities
• 39Ca , 19Ne
150
21Na
in trap
Ba MOT
100
50
0
X 100
-80 -60 -40 -20
0 20
Detuning of l 1 [MHz]
TRImP Separator
Target
SHT2
E1
IFP
NaI
NaI
E2
NaI
MCP
MOT
E3
FFP
TI
NaI
NaI
Step
degrader
NaI
neutralizer
TRImP
Scientific Personnel 2007-2008
Faculty
PhD student
Technical {2 + pool}
Theory group
Undergrad.
Atomic Physics
group
Foreign stud.
Postdoc
Fundamental Interactions group
AGOR group
+ operators & technici
In-House Core Program
T – violation:
• b-decays
• 21Na
• EDMs
• Ba/Ra – atom
• trapping
• polarization
• deuteron
P – violation:
• Single Ion
• sin2 ϴW
• clock
Lorentz - violation:
• Weak Interactions
Countrate [106 /s]
• ‘a’ & ‘D’ coefficients
• lifetime, branching ratio
• Future Possibilities
• 39Ca , 19Ne
150
21Na
in trap
Ba MOT
100
50
0
X 100
-80 -60 -40 -20
0 20
Detuning of l 1 [MHz]
TRIX: Trapped Radium Ion eXperiments
Atomic parity violation &
All-optical atomic clock
Atomic Parity Violation
The weak interaction gives the nucleus a weak charge
q
q
γ
e-
e-
Coulomb interaction (conserves parity)
• Mediated by photons, massless, so long-range
• Gives the atomic spectrum and E1 etc. transitions
• Strength scales ~ Z
• Nucleus has an electric charge
Weak interaction (violates parity)
• Mediated by Z0 bosons, mass ≈ 91 GeV, so short-range
• Violation of selection rules (E1PNC transitions)
• Strength scales ~ Z3
• Nucleus has also a weak charge Qw
q
q
Z0
e-
Weak charges of nuclear quarks add coherently:
Qw = –N+(1–4 sin2θW)Z + small radiative corrections + “new physics”
where θW is the weak mixing (or Weinberg) angle.
e-
The running of the Weinberg angle
A poorly tested prediction of the Standard Model
High energy (near the Z0-pole)
• LEP @ CERN
A. Czarnecki and
W.J. Marciano,
Nature (2005).
Low energy: atomic parity violation (APV)
• Cesium atoms: 6S–7S transition
 Experiment: 0.35% by Wieman group, Boulder; theory: 0.5%
• Barium ions: 6S–5D3/2 transition
 Experiment: Fortson group, Seattle; theory: 0.5%
• Francium atoms: 7S–8S transition
 Experiment: Stony Brook and Legnaro
• Radium ions: 7S–6D3/2 transition
 Experiment & theory: KVI, University of Groningen
Medium energy
• E158 @ SLAC
• parity viol. electron
scattering
• NuTeV @ Fermilab
• neutrino scattering
• Qweak @ TJNAF
• Qw(p) of the proton
The case for radium
Why the radium ion is the ideal candidate
E1APV
Advantages of
Ra+
vs. Cs, Fr,
Ba+
• Heavy (APV signal scales faster than ~ Z3)
• “Easy” lasers: semiconductor diodes
• Single ion techniques:
 Superior control of systematics
 Novel -frequency- measurement
method: light shifts
S-S
S-D
Cs
0.9
Ba+
2.2
Fr
14.2
Ra+
46.4
Atomic Parity Violation
in a Radium ion
7P
Radium Ion
6D
≠
E1APV + E2
parity
7S + a bit of 7P
q
q
q
γ
e
q
Z0
e
Electromagnetism
-
e-
e-
Weak interaction
Atomic parity violation in Ra+
Interference of E2/E1APV in AC Stark shift
Interference produces differential light
shift of ground state m-levels:
2
| m 'm |2 =| mE 2'm + mAPV
'm |
Ra+
7P3/2
* E2
| mE 2'm |2 +2 Re( mAPV
'm  m 'm )
7P1/2
6D5/2
6D3/2
Repump
λ = 1.08 μm
Off-resonant
laser
Cooling &
detection
λ = 828 nm
E2
λ =468 nm
Ddiff = Dpnc
APV
E1
m=+1/2
w0
7S1/2 (+ εn n P1/2)
m=-1/2
D l ,m w  =
I

4 l ,m, w

ˆ
E1+E2
l , m | E  r | l , m
w 0l ,l   w
2
w0
w0 + Ddiff
From here to the Standard Model
there and back again
1) measure the AC stark shift  get E1 amplitude from differential
part of the light shift
2) calculate atomic
* E2
| mE 2'm |2 +2 Re( mAPV
'm  m 'm )
theory to < 1% and extract the weak charge
E1PNC = 46.4(1.4)  1011iea 0 ( Qw / N )
3) add a bit of QFT and find the Weinberg angle
OR NEW PHYSICS
Qw = –N+(1–4 sin2θW)Z + small radiative corrections + “new physics”
Optical Atomic Clock
Spin-off project
214/226 - Ra +
Based on 7S1/2-6D3/2 E2 transition:
7P 1/2
• Narrow (Δν ~ 1 Hz)
• Optical regime (4 x 1014 Hz)
6D 3/2
E2
High quality clock based on off-theshelf available semiconductor lasers
clock laser
λ = 828 nm
7S 1/2
223 - Ra +
F=2
7P 1/2
F=1
6D 3/2
E2
clock laser
λ = 828 nm
F=2
7S 1/2
F=1
F=3
F=0
F=1
F=2
• Absence of electric
quadrupole shift in 223Ra
(I=3/2)
•Heaviest system: 2nd order
Doppler ~ 1/mass
• Ra+: search for variation of
fine structure constant
Status & outlook
From here to sin2(Θw)
First trapping & optical detection of
radium ions in 2009!
PMT counts [a.u.]
Experiment
• Multiple ion traps have been constructed
• Ba+ & Ra+ lasers set up in new, dedicated laser lab
• Ra isotopes produced with AGOR cyclotron and
TRIμP facility
Done!
Time [s]
Theory
• 3 % calculation finished, pushing for < 1 % accuracy now
(inclusion of Breit, neutron skin and RCC improvements)
11
E1APV
iea 0 ( Qw / N )
PNC = 46.4(1.4)  10
L.W.Wansbeek et al., Phys. Rev.
• Precise experimental input is an absolute necessity (e.g.
A 78, 050501 (2008)
D-state lifetimes, E1 transition strengths and hyperfine
constants)
 First experimental goals
• Study of different isotopes
The TRIμP radium ion experiment at the KVI
Crew
Experiment
O. Böll (bachelor student)
G. S. Giri (PhD student)
O. O. Versolato (PhD student)
L. Willmann
K. Jungmann
You?
Theory
Interested?
L. W. Wansbeek (PhD student)
B. K. Sahoo (postdoc)
R. G. E. Timmermans
Funding
International collaborators
• NWO Toptalent (OV)
B. P. Das (India)
• NWO VENI (BS)
N. E. Fortson (USA)
• FOM Projectruimte (KJ, RT)
Bonus material 1:
Electron shelving method
Bonus material 2:
Trapping ions in a Paul trap
Are there quantum jumps?
"…we never experiment with just one atom or (small)
molecule. In thought experiments we sometimes assume that
we do; this invariably entails ridiculous consequences."
Erwin Schrödinger (1952)
Precision experiments on a single trapped ion
how to trap an ion using E&M
Maxwell !
Harmonic
potential
3D case
No charge
enclosed
Problem: Only 2D trapped BUT 1D repulsive!
The Paul trap
and its mechanical analogue
Needed:
hyperbolically shaped surface
Solution: Apply a rotating potential!