The New Experiment at PSI

Martin Fertl on behalf of the nEDM collaboration nedm.web.psi.ch

and on behalf of the UCN Project team Martin Fertl BNL Seminar, 10/28/2010 2 The neutron EDM collaboration

M. Burghoff, S. Knappe-Grüneberg, A. Schnabel, L. Trahms Physikalisch Technische Bundesanstalt, Berlin

G. Ban, Th. Lefort, Y. Lemiere, E. Pierre, Laboratoire de Physique Corpusculaire, Caen G. Quéméner

K. Bodek, St. Kistryn, J. Zejma Institute of Physics, Jagiellonian University, Cracow

A. Kozela Henryk Niedwodniczanski Inst. Of Nucl. Physics, Cracow

N. Khomutov Joint Institute of Nuclear Reasearch, Dubna

P. Knowles, A.S. Pazgalev, A. Weis Département de physique, Université de Fribourg, Fribourg

P. Fierlinger, B. Franke1, M. Horras1, F. Kuchler, G. Petzoldt Excellence Cluster Universe, Garching

D. Rebreyend , G. Pignol Laboratoire de Physique Subatomique et de Cosmologie, Grenoble

G. Bison Biomagnetisches Zentrum, Jena

S. Roccia, N. Severijns Katholieke Universiteit, Leuven

G. Hampel, J.V. Kratz, T. Lauer, C. Plonka-Spehr, Inst. für Kernchemie, Johannes-Gutenberg-Universität, Mainz N. Wiehl, J. Zenner1

W. Heil, A. Kraft, Yu. Sobolev2 Inst. für Physik, Johannes-Gutenberg-Universität, Mainz

I. Altarev, E. Gutsmiedl, S. Paul, R. Stoepler Technische Universität, München

Z. Chowdhuri, M. Daum, M. Fertl, R. Henneck, J. Krempel, B. Lauss, Paul Scherrer Institut, Villigen A. Mtchedlishvili, P. Schmidt-Wellenburg, G. Zsigmond

K. Kirch1, F. Piegsa Eidgenössische Technische Hochschule, Zürich also at: 1Paul Scherrer Institut, 2PNPI Gatchina PhD students www.psi.ch

Martin Fertl BNL Particle Physics Seminar, 10/28/2010 4 Paul Scherrer Institut

• Nuclear and renewable energy Proton cycolotron: • Nuclear safety 600 MeV, 2.2 mA, 1.3 MW • Structural biology, chemistry muons, pions and for fundamental and applied research

New project: SwissFEL New UCN source

Proton therapy

Swiss Light Source (SLS) synchrotron radiation

Martin Fertl BNL Particle Physics Seminar, 10/28/2010 5 What caused the ?

Andrei Sakharov 1967: B-violation C & CP-violation thermal non-equilibrium [JETP Lett. 5 (1967) 24]

Martin Fertl BNL Particle Physics Seminar, 10/28/2010 6 EDMs and symmetries

 σ σ      dH  E μ   B  σ σ  Thus a nonzero electric dipole moment violates  σ σ  P, T symmetry and, assuming  dPH  )E( μ     HB CPT conservation, σ alsoσ CP.

 (σ) (σ)       dTH  E  μ     HB  σ σ 

Purcell and Ramsey, Phys. Rev. 78, 807 (1950) Landau, Nucl. Phys. 3, 127 (1958) Ramsey, Phys. Rev. 109, 225 (1958)

Martin Fertl BNL Particle Physics Seminar, 10/28/2010 7 Origin of EDMs

need CP-odd phases in fundamental theory d these values should be deduced neutron & proton EDMs

experimentally accessible EDMs of paramagnetic atoms & molecules EDMs of diamagnetic atoms Tl,Cs..,YbF, Hg, Xe, Ra, Rn .. PbO,ThO,HfF +,WC..

Adapted from: A. Ritz, NIMA 611 (2009) 117-123 Martin Fertl BNL Particle Physics Seminar, 10/28/2010 8 The strong CP problem QCD

Why is θQCD so small?

Martin Fertl BNL Particle Physics Seminar, 10/28/2010 9 The SUSY CP problem SUSY

Pospelov, Ritz, Ann. Phys. 318(2005)119 for

MSUSY = 500GeV, tan b = 3

Why is ΦSUSY so small?

Martin Fertl BNL Particle Physics Seminar, 10/28/2010 10 History of nEDM searches

10-19

-20 cm] 10 ORNL, Harvard e current best nEDM limit: 10-21 MIT, BNL -26 LNPI dn < 2.9·10 e cm (90% C.L.) -22 10 Sussex, RAL, ILL C.A.Baker et al., PRL 97, 131801 (2006) 10-23 10-24

-25 Sensitivity goals at PSI 10 Intermediate: -26 ▼ 10 -27 dn < 5 x 10 e cm (95% C.L.) 10-27 Supersymmetry predictions Final: 10-28 -28 dn < 5 x 10 e cm (95% C.L.) 10-31 StandardmodelStandardmodel calculationsincluding CKM -32

Neutron EDM Upper Limit [ EDMNeutron Limit Upper 10 1950 1960 1970 1980 1990 2000 2010 2020 Year of Publication

Martin Fertl BNL Particle Physics Seminar, 10/28/2010 11 ultracold neutrons (UCN) are storable neutrons: Ekin < 330 neV, v < 8 m/s,

λ≈500 Å, T ≈ 3 mK

Simulation of a neutron bottle with confining forces: • Gravity: potential energy 100 neV/m • Material optical potential: < 330 neV E. Fermi, 1946 , Ya. B. Zeldovich Sov. Phys. JETP 9, 1389 (1959)

vn

2 VF=mv C /2

1.5 T • Magnetic field gradient: potential energy ± 60 neV/T

Martin Fertl BNL Particle Physics Seminar, 10/28/2010 12 From cold to ultracold cold neutron UCN

phonon

converter sketch adapted from Chen-Yu Liu, University of Indiana converter types:

• sD2 (PSI, LANL, NCSU, FRM2,…) • sfHe (CryoEDM, SNS, ILL, PNPI,…)

Martin Fertl BNL Particle Physics Seminar, 10/28/2010 13 The PSI UCN source

towards muon and pion beams

Beam dump

Proton cyclotron: 600 MeV, 2.2 mA, 1.3 MW

• UCN Source commissioning started fall 2009 • Expect 1000 UCN/cm3 in typical experiments

(compare to currently 30 UCN/cm3 at ILL)

• nEDM setting up since middle of 2009 nEDM

Martin Fertl BNL Particle Physics Seminar, 10/28/2010 14 2 m3 volume storage trap

-3 UCN guide exp≈ 1000 cm

vacuum compare with typical 30 cm-3 at ILL PF2

The PSI UCN source

30 liters solid D2

p-beam 1.3 MW

3.6 m3 D O 2 • high power (1.3 MW)

• low duty cycle (1%) Martin Fertl BNL Particle Physics Seminar, 10/28/2010• multi-user capability 15

The PSI UCN Source delivery of tank: June December Sept. 04, 2008 2009 2009

spallation target bottle

Martin Fertl BNL Particle Physics Seminar, 10/28/2010 16 The PSI UCN Source

b) 1200 DecDec.18 18, 2009: first beam on target 15:38 #32 - 2mA 1000

500 mm (20”) 800 #29 - 1mA

600

Counts

200 mm #1 kick 14:00 (7.9”) 0.5 400mm AlMg3 0.02” 200

cooling channels made by 40 60wire erosion 80 100 120 140 2 × 1.5 mm AlMg4.5Mn 0.06” Time (min)

Martin Fertl BNL Particle Physics Seminar, 10/28/2010 17 The PSI UCN Source

Martin Fertl BNL Particle Physics Seminar, 10/28/2010 18 The PSI UCN source

20.09.2010

1m 3.3ft

inserting the last UCN guide

UCN storage volume

Martin Fertl BNL Particle Physics Seminar, 10/28/2010 19 Ramsey technique for nEDM

compare neutron clock with stable external reference

working points

Martin Fertl BNL Particle Physics Seminar, 10/28/2010 20 Measurement principle

try to detect a change of the Larmor precession frequency Δ for parallel and anti-parallel B (~1 T) and E fields (~10 kV/cm)

statistical sensitivity only limited by the uncertainty principle:

α Visibility of resonance E Electric field

T Time of free precession

N Number of neutrons

Martin Fertl BNL Particle Physics Seminar, 10/28/2010 21 nEDMflying nEDMapparatusexperiment

field compensation coils

ILL, Grenoble PSI, Villigen

Martin Fertl BNL Particle Physics Seminar, 10/28/2010 22 nEDM apparatus

UCN

Martin Fertl BNL Particle Physics Seminar, 10/28/2010 23 magnetic field requirements I

only if

statistical sensitivity goal: α Visibility of resonance (0.75) E Electric field strength (12 kV/cm)

T Time of free precession (150 s)

N Number of neutrons (350000)

B field requirement: σ(B)  100 fT per one Ramsey cycle (~ 500s)

Martin Fertl BNL Particle Physics Seminar, 10/28/2010 24 and SFC

two systems:

• 199Hg comagnetometer

• array of laser-driven optically pumped Cs-magnetometers:

4 HV - compatible sensors

8 sensors on ground potential

6 current coils for active sourrounding field compensation (SFC)

Martin Fertl BNL Particle Physics Seminar, 10/28/2010 25 199Hg comagnetometer

• polarized 199Hg atoms sample magnetic field inside the UCN precession chamber at the same time as the UCN (cohabiting)

• optical readout of free precession with light from 204Hg lamp • performance: σ(B) ~ 40 fT per 100 s run

29.998

30 pT uncorrected frequency

29.997 corrected Hg comagnetometer correct the UCN precession neutron frequency [Hz] frequency with Hg 29.996 precession frequency

29.995 0 1020304050 t [h] Martin Fertl BNL Particle Physics Seminar, 10/28/2010 26 SFC performance

6 rectangular coils to actively stabilize the surrounding magnetic field

measured with Cs magnetometer array

SFC off

SFC on work in progress

Martin Fertl BNL Particle Physics Seminar, 10/28/2010 27 systematic error contributions

Martin Fertl BNL Particle Physics Seminar, 10/28/2010 28 Cs magnetometer array

4 HV and vacuum compatible HV protection cover Cs magnetometer

Plexiglas optical fiber gallows

UCN and Hg precession volume

survey magnetic fields related to theUCN doors/shutters (“door cavity dipole” ) measure the “uncompensated B drift” (HV reversal related) optical fibers, vacuum magnetic field gradients8 non-HV (geometric vacuum phase compatible effect) Cs magnetometer

Martin Fertl BNL Particle Physics Seminar, 10/28/2010 29 magnetic field requirements II

spatial magnetic field gradients → UCN depolarization (center of mass effect) geometric phase effect

33 individual trim coils outside the vacuum tank to shape the magnetic field

Martin Fertl BNL Particle Physics Seminar, 10/28/2010 30 magnetic field mapping

to address “other dipole fields” and “quadrupole differences”

Martin Fertl BNL Particle Physics Seminar, 10/28/2010 31 magnetic field mapping

Martin Fertl BNL Particle Physics Seminar, 10/28/2010 32 magnetic field mapping map magnetic field in UCN precession chamber with all subsystems installed

+90º HV feed through 0º

Martin Fertl BNL Particle Physics Seminar, 10/28/2010 33 Magnetic screening large pieces are magnetically screened with SQUID array at PTB Berlin BMSR2 15 m

6 m

2.9 m

Martin Fertl BNL Particle Physics Seminar, 10/28/2010 34 Magnetic screening

bottom electrode before degaussing bottom electrode after degaussing 200 pTpp 20 pTpp

isolines 2 pTpp

Martin Fertl BNL Particle Physics Seminar, 10/28/2010 35 Magnetic screening gradiometer setup to magnetically screen small parts before implementation

2 washers from same batch

0.02 nT 1500 nT

holding field in nEDM: 1000 nT

Martin Fertl BNL Particle Physics Seminar, 10/28/2010 36 Further developments

several further improvements have been developed in the collaboration and will be used in the new nEDM measurement:

• new high count rate UCN detectors (~105 cts/s each, 9 detectors) • new spin analyzing foil (single crystal iron foil) • thermal stabilization of Mu-metal shield • new degaussing system for the Mu-metal shield • new bipolar HV power supply • replace massive metal pieces with metal coated plastics

Martin Fertl BNL Particle Physics Seminar, 10/28/2010 37 Summary and outlook

• nEDM experiment successfully transferred to PSI

• PSI UCN source at the end of commissioning → cool down in November 2010

• Design of n2EDM experiment has started to improve sensitivity to 5 x 10-28 ecm (2012+).

Thank you!

Martin Fertl BNL Particle Physics Seminar, 10/28/2010 38