Display the Experiment Proposals for S1218

Experiment: S1218

Towards an optical parity violation experiment in francium: Spectroscopy of the 7s - 8s transition

by the FrPNC group

Pending (Stage 1)
Spokespersons:
G. Gwinner (University of Manitoba)

Original Proposal for EEC meeting 200812S

Table of Contents

Detailed Information

Complete/Merged PDF S1218_200812S_merged.pdf
Form data only S1218_200812S.pdf
Detailed Statement proposal2.pdf (747.42 kB)

Beam Shift Summary

12-hr ShiftsBeam Line / channelPriority
New Beam Requests
 60 BL2A/ISAC
Once a francium beam is available
Committee Recommendations
 0 H

This program of atomic PNC in Fr has fundamental aims: the measurement of the Fr weak charge could be one of the best low energy tests of the Standard Model and the anapole moment measurements could provide crucial information on hadronic weak interactions.  We note that the recent improvement in atomic PNC theory for Cs supports the development of the necessary Fr atomic theory.  The timely completion of these difficult measurements will benefit greatly from a second ISAC beam line.  The proposed observation of the highly forbidden 7s-8s transition is a useful first step.

The committee recommends Stage one approval at high priority

 


Membership

G. Gwinner University of Manitoba Associate Professor 50 % Spokesperson
C. De Oliveira University of Manitoba Student (PhD) 100 %  
A. Perez Galvan University of Maryland Student (PhD) 50 %  
D. Sheng University of Maryland Student (PhD) 50 %  
J.A. Behr TRIUMF Research Scientist 30 %  
L.A. Orozco University of Maryland Professor 30 %  
E. Gomez San Luis Potosi, Mexico Assistant Professor 20 %  
M.R. Pearson TRIUMF Research Scientist 20 %  
S. Aubin William & Mary Assistant Professor 20 %  
D.G. Melconian Texas A&M University Assistant Professor 10 %  

Basic Information

Date Submitted
2008-11-14 14:11:40
Date Experiment Ready
2010-06-01
Summary *

The 7s - 8s atomic transition in francium is considered one of the most promising candidates for an atomic parity nonconservation (APNC) experiment in heavy atoms. In francium, the APNC effect is 18 times larger than in Cs, where the best experiment so far has been carried out. In the LHC era, low energy experiments still have an important role to play, and in terms of their sensitivity to different types of 'new' physics beyond the Standard Model, APNC and electron scattering experiments such as Qweak and E158 are complementary. Recently, great progress has been made in the relevant atomic structure calculations, and the PREX experiment at Jefferson Lab will provide significantly improved neutron radius information. This constitutes an excellent basis for APNC experiments in isotopes of francium.

As a first step towards APNC measurements, we propose to investigate the 7s - 8s optical transition. Spectroscopy of faint transitions on-line with a radioactive sample of atoms is naturally more challenging than work with stable atoms. It is important to develop a robust procedure that allows us first to locate the transition at all, and then to perform increasingly sophisticated experiments to explore the more subtle aspects with increasing precision. The initial setup should be as simple as possible, while a final version of the on-line trap will be capable of housing an APNC setup. We will explore the Stark-induced amplitudes and the relativistic and hyperfine-induced M1 amplitudes. Understanding these amplitudes is critical to the interpretation of APNC data. In addition, these measurements will allow the careful development of an on-line laser trap setup capable of supporting an APNC experiment.

We will be able to exploit the strong synergies between this proposal and the already approved Fr hyperfine anomaly (E1010) and anapole (E1065) experiments by sharing essentially all the infrastructure.

Plain Text Summary *
We propose to investigate the highly forbidden 7s-8s optical transition in laser trapped and cooled francium atoms as a precursor experiment to an atomic parity nonconservation experiment. The ultimate goal is to search for 'new' physics beyond the Standard Model of particle physics, using precise laser spectroscopy and atom trapping and cooling techniques.
Primary Beam Line
ISAC 2A
ISAC Facilities
ISAC Facility
Other
Secondary Beam
Isotope(s)
Fr-210
Energy
30
Energy Units
keV
Intensity Requested (pps)
10^7 or more(pps)
Minimum Intensity (pps)
10^6(pps)
Experiment Support
TRIUMF Support (Resources Needed)

 

Beam line to deliver 10 keV francium ions to a neutralizer.

Electromagnetically shielded enclosure in experimental hall with temperature control and air filter for lasers and rf equipment, 5.5 m by 6 m.

Mechanical design help for radiation shielding in the neutralizer region.

 

NSERC

• NSERC, SAPIN (G. Gwinner); Investigations toward atomic parity nonconservation and anapole measurements in francium (support through 2010)

• NSERC TRINAT project grant (J.A. Behr, K.P. Jackson, M. Pearson, G. Gwinner); continuing support through 2012 has been applied for.

• NSERC Francium project grant (G. Gwinner, J. A. Behr, M. Pearson); plan to apply for this grant in fall 2009 once actinide target plans are firm

Other Funding

• NSF (USA) Anapole moment studies in francium (L. A. Orozco)

Safety Issues

 

Yields of > 10^8 /sec short-lived Fr alpha emitters will be delivered to the main ISAC floor. Most of the activity is alpha radiation and will be contained in the trap region. Mechnical design support will be requested for lead or heavymet shielding near the trap volume. Mechanical pump exhausts will be filtered using the experience gained from the E929 radon EDM experiment tests with xenon. Certain masses produce long-lived 206,208,209,210 Po and will require careful precautions as polonium is quite volatile. The safety officer will be M. Pearson, who has experience gained at experiments at ISOLDE and at Stony Brook.

 

Proposals and Progress Reports

200812S (Original Proposal)