S929: Radon EDM ProgressGordon Ball,1 John Behr,1 Tim Chupp,2 David Cross,1 Celia Cunningham,2Greg Demand,3 Alejandra Diaz-Varela,3 Martin Djongolov,1 Ryan Dunlop,3Paul Finlay,3 Adam Garnsworthy,1 Paul Garrett,3 Katie Green,3 GregHackman,1 Mike Hayden,4 Drew Jamieson,3 Carolyn Kierans,1,4 JamieKilkenny,1 Wolfgang Lorenzon,2 Matthew Pearson,1 Tim Raben,2 EvanRand,3 Chandana Sumithrarachchi,3 Carl Svensson,3 Eric Tardiff,1 SmarajitTriambak,1 Scott Williams,1 Jan Zirnstein2

1TRIUMF2University of Michigan

3University of Guelph4Simon Fraser University

Spokesmen: T. Chupp and C. Svensson

Outline

• General Motivation for the Radon EDMExperiment

• Natural Xe AFP Studies• The July Run

– Apparatus– Goals

• Gas Transfer• 121Xe polarization measurements

EDMs as a Source of CP Violation• An EDM is a separation of charge

along J:

• The EDM, d, is a polar vector and the angular momentum, J, is an axial vector.• Under parity and time reversal transformations these

quantities behave oppositely.• A non-zero gd would then indicate P- and T-violation, and

by the CPT theorem this implies CP violation, which isnecessary to explain the baryon assymmetry of theuniverse.

+-

-+

P or T

gd > 0 gd < 0

〈datom〉= gd〈J〉

The Current Radon EDM Apparatus

GV3

foilIV2 IV0 To Beamline

Cs beam

Turbopump

GV2

GV4

GV1

Coldfinger

Glass Valve

Brass Valve (CV)

Cell

To Roughing System

TurbopumpGV0

Baratron

Gas Loading ChamberConvectron

NitrogenStorage

DV1 RV4

Ion Gauge

795 nm Diode LaserPolarization Optics

Xenon AFP Studies

• Natural xenon contains 129Xe (I=1/2) and 131Xe (I=3/2).• Allowed us to confirm that the polarization apparatus could

successfully polarize 131Xe.

Cell 795 nm Diode LaserPolarization Optics

Pickup Coils

RF Coils

Helmholtz Coils

129Xe DataPeak Height ~ 0.27 V

131Xe DataPeak Height ~ 0.04 V

129Xe Polarization Build-Up

Goals of the July Run

• Measure a consistent (fill-to-fill)polarization signal for 121Xe.

• Measure optical pumping transients.• Measure and optimize the transfer

efficiency from foil to cell.• 121Xe magnetic moment measurement.

The Current Radon EDM Apparatus

GV3

foilIV2 IV0 To Beamline

Cs beam

Turbopump

GV2

GV4

GV1

Coldfinger

Glass Valve

Brass Valve (CV)

Cell

To Roughing System

TurbopumpGV0

Baratron

Gas Loading ChamberConvectron

NitrogenStorage

DV1 RV4

Ion Gauge

795 nm Diode LaserPolarization Optics

• A: Moved lead shieldaway from foil detector,wait for cell to cool.

• B: Pump out cell, coolcoldfinger.

• C: Heat foil to transferxenon to coldfinger

• D: Warm coldfinger torelease xenon into celland coldfinger volume.

• E: Push xenon into cellwith nitrogen.

• F: Move lead back infront of foil detector.

A B C FD E

121Xe Decay Scheme

121Xe γ-ray Spectrum132.8

175.8 &177.7

252.7

310.5

433.4

445.2

529.1649.7

Run 1906

Polarization Signal (Preliminary)

Preliminary Preliminary

PreliminaryPreliminary

Work in Progress

• The above does not include corrections fordetector efficiency, dead time, or pileup.

• Once the detector efficiency calibrations arecomplete, we will determine the efficiency of ourgas transfer apparatus.

• Fit all 15 peaks in all data sets to look at thedependence of any polarization signals on theexperimental conditions (cell temperature,detector position).

529.1 keV averages: Bon = 1.032 ± 0.011 Boff = 1.006 ± 0.010

649.7 keV averages: Bon = 1.046 ± 0.015 Boff = 1.035 ± 0.014