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Search for an EDM of the neutron at PSI

Klaus Kirchfor the nEDM collaboration

nedm.web.psi.chLepton Moments 2010

[email protected] 2Cape Cod, July 2010

The Neutron EDM Collaboration

also at: 1Paul Scherrer Institut, 2PNPI Gatchina, 3ETH Zürich

The Neutron EDM CollaborationM. Burghoff, S. Knappe-Grüneberg, A. Schnabel, L. T rahms

G. Ban, Th. Lefort, Y. Lemiere, O. Naviliat-Cuncic, E. Pierre 1, G. Quéméner

K. Bodek, St. Kistryn, J. Zejma

A. Kozela

N. Khomutov

M. Kasprzak, P. Knowles, T. Spetzler , A. Weis

P. Fierlinger , B. Franke 1, M. Horras 1, F. Kuchler , G. Petzoldt, G. Pignol

D. Rebreyend

G. Bison

S. Roccia, N. Severijns

G. Hampel, J.V. Kratz, C. Plonka-Spehr, N. Wiehl, J. Zenner 1

W. Heil, A. Kraft , T. Lauer, Yu. Sobolev 2

I. Altarev, E. Gutsmiedl, S. Paul, R. Stoepler

Z. Chowdhuri, M. Daum, M. Fertl 3, R. Henneck, B. Lauss, A. Mtchedlishvili, P. Schmidt-Wellenburg, G. Zsigmon d

C. Grab, K. Kirch 1, F. Piegsa

Physikalisch Technische Bundesanstalt, Berlin

Laboratoire de Physique Corpusculaire, Caen

Institute of Physics, Jagiellonian University, Cracow

Henryk Niedwodniczanski Inst. Of Nucl. Physics, Cracow

Joint Institute of Nuclear Reasearch, Dubna

Département de physique, Université de Fribourg, Fribourg

Excellence Cluster Universe, Garching

Laboratoire de Physique Subatomique et de Cosmologie, Grenoble

Biomagnetisches Zentrum, Jena

Katholieke Universiteit, Leuven

Inst. für Kernchemie, Johannes-Gutenberg-Universität, Mainz

Inst. für Physik, Johannes-Gutenberg-Universität, Mainz

Technische Universität, München

Paul Scherrer Institut, Villigen

Eidgenössische Technische Hochschule, Zürich

Our strategyPhase I:

Operated nEDM@ILL (-2008)Moved nEDM to PSI in March 2009Design of n2EDM, related R&D

Phase II:Operate nEDM@PSI (2009-2012) Sensitivity goal: 5x10-27ecmSetup of n2EDM, continued R&D

Phase III:Operate n2EDM (2012-2015)Sensitivity goal: 5x10-28ecm

Optimizein-vacuum,

room-temperaturetechnique


nEDM Apparatus

Room temperature experimentRamsey technique of separated oscillatory fieldsMercury co-magnetometer to monitor magnetic field

The EDM limits to

date

10-26

10-20 10-20

10-26

1950 2000

ED

M u

pper

limit

[ecm

]

Smith, Purcell, Ramsey PR108(1957)120

[e cm]

.

Electro-weak standard modelexpectation: ~10-32 e•cm

RAL-Sussex-ILLdn < 2.9 x 10–26 e cm

C.A.Baker et al., PRL 97 (2006) 131801

The EDM limits to

date

10-26

10-20 10-20

10-26

1950 2000

ED

M u

pper

limit

[ecm

]

Smith, Purcell, Ramsey PR108(1957)120

[e cm]

.

Electro-weak standard modelexpectation: ~10-32 e•cm

RAL-Sussex-ILLdn < 2.9 x 10–26 e cm

C.A.Baker et al., PRL 97 (2006) 131801

Limited statistics


Phase I: Sussex-RAL-ILLApparatus at ILL


Phase I data: physics resultsNew constraints on Lorentz invariance violation fro m the neutron electric dipole momentI. Altarev et al., arXiv:1006.4967

Test of Lorentz invariance with spin precession of ultracold neutronsI. Altarev et al., PRL103(2009)081602

Neutron to Mirror-Neutron Oscillations in the Prese nce of Mirror Magnetic FieldsI. Altarev et a., PRD80(2009)032003

Direct experimental limit on neutron -- mirror-neutr on oscillationsG. Ban et al., PRL99(2007)161603

[email protected] 10Cape Cod, July 2010 Feb. 17th, 2009

3.6 m3 D2O

ρUCN~6000 cm-3

2 m3 volumestorage trap

ρ ~ 2000 cm-3 ρexp> 1000 cm-3

The PSI UCN source

UCN guide

30 liters solid D2

vacuum

• high power (1.3 MW)• low duty cycle (1%) • multi-user capability

compare with typical 10 cm-3 at ILL

p-beam1.3 MW


Proton Accelerator Facility

nEDMττττn

µµµµp Lamb ShiftFASTMuLan/MuCap/MuSun

MEG

PEN

PIF

Inhouse particle physics:

UCN target station hit by protons with600 MeV, 2.2 mA at 1% duty cycle


Beam dump

nEDMττττn

• Expect 1000 UCN/cm3 in typical experiments (compare to currently 10 UCN/cm3 at ILL)

• nEDM setting up since middle of 2009• Source commissioning started end of 2009• First UCN by fall 2010

PSI UCN Source


First proton pulse on UCN spallation targetDecember 15, 2009

signal distribution on oscilloscope monitoring fast neutrons from spallation production - 100 µµµµA beam current / 5 ms pulse length

before pulse(background)

start of pulse

during pulse

2 s after pulse

B.Lauss / L.Goeltl


Source assembly

Storage volume in assembly position

Top view into UCN storage volume


Installing the UCN storage volume

Thermal shield

Fe radiation shielding

UCN vacuum tank

vertical neutron guide


Trim and correction coils

33 coils designed, installed, and characterized

Numerical & manual optimization of currents

Top, bottom, and Helmholtz

Left & right side coils


Phase II: Setup at PSI

SC polarizer Compensationcoil system

nEDMapparatus

Air conditioningthermal stabilization


Individual air conditioning

Upper floor ±0.1˚C

Lower floor ±1˚C

Thermal changes affect B0 stability

Tests ongoing

Thermal stabilization

Work in progress


Surrounding field compensation

w/o SFC

w SFC

B. Franke et al.

Work in progress


Example for trim coil optimization


Present status of Fluxgate investigations

Allow for optimizing all field components to better than 0.5 nTNormalized to field modulus (~1µT) and measured for all field components within innermost 45 liters:

peak to peak differences ~0.2% sigma < 0.04%

Degaussing reproducible to better than fluxgate precision (within ~150 pT)


Cs magnetometer intercalibration



average deviation from mean:

Cs 1: - 5 ± 4 pT

Cs 2: + 14 ± 4 pT

Cs 3: + 2 ± 4 pT

Cs 4: -11 ± 5 pT

Work in progress

UCN

See poster by Martin Fertl and Johannes Zenner


Adding Cs magnetometry4 HV and vacuum compatible Cs magnetometerHV protection cover

UCN and Hg precession volume

8 non-HV vacuum compatible Cs magnetometer

UCN

plexiglassoptical fiber gallows

optical fibers, vacuum


α = 0.75

E = 12 kV/cm

T = 150 s

N = 350′000

= 4 x 10-25 ecm / cycle

= 3 x 10-26 ecm / day

= 3 x 10-27 ecm / year

400 s

200 nights

After 2 years*, statistics onlydn = 0: |dn| < 4 x 10-27 ecm (95% C.L.)Obtain same figures with

E=10kV/cm, T=130s, 200s cycle

Statistical Sensitivity

* 200 nights each


Systematics

1.37

0.01

0.10

0.40

0.06

0.90

0.20

0.40

0.02

0.10

0.03

0.60

0.40

0.10

σ (at PSI)[10-27 ecm]

7.19-3.8Total

0.010.0ac fields

0.100.0Leakage currents

0.400.0Elastic forces

0.30-0.4Hg atom EDM

2.400.0Uncompensated B drift

0.200.0νHg light shift (direct)

0.803.5νHg light shift (geo phase)

0.020.0Second-order v××××E

1.000.0v××××E rotational

0.030.0v××××E translational

2.00-1.3Quadrupole difference

6.000.0Other dipole fields

2.00-5.6Door cavity dipole

σ (see Ref.) [10-27 ecm]

Shift (see Ref.) [10-27 ecm]Effect

PRL 97, 131801 (2006)


Systematics

1.37

0.01

0.10

0.40

0.06

0.90

0.20

0.40

0.02

0.10

0.03

0.60

0.40

0.10

σ (at PSI)[10-27 ecm]

7.19-3.8Total

0.010.0ac fields

0.100.0Leakage currents

0.400.0Elastic forces

0.30-0.4Hg atom EDM

2.400.0Uncompensated B drift

0.200.0νHg light shift (direct)

0.803.5νHg light shift (geo phase)

0.020.0Second-order v××××E

1.000.0v××××E rotational

0.030.0v××××E translational

2.00-1.3Quadrupole difference

6.000.0Other dipole fields

2.00-5.6Door cavity dipole

σ (see Ref.) [10-27 ecm]

Shift (see Ref.) [10-27 ecm]Effect

After 2 years, statistics & systematicsdn = 0: |dn| < 5 x 10-27 ecm (95% C.L.)or, e.g., dn = 1.3 x 10-26 ecm (5σ)

PRL 97, 131801 (2006)

PTB Berlin BMSR-2

Cryostat containing SQUID array

Non-magnetic patient bedused as support forsamples. Movable alongy-axis. NEW: wooden tablemovable along x-axis

x

z

y

Typical measurement setup at PTB

Electrode maps

Results: ElectrodesRemeasured bottom electrode, after degaussing and some mechanical work:

Maximum peak to

peak: ~16-20 pT!

A. Schnabel, G. Petzoldt et al.

Special feature: co-magnetometer

·· · · · · ·

· ·· · ··· ··· ·· · ··

·· ·

BoEUCN

199Hg

K.Green et al., NIM A 404 (1998) 381 P. G. Harris et al., PRL 82 (1999) 904

199Hg co-magnetometer

50 pT

Very important for nEDM analysis:


Systematics: B-field gradients

R depends on vertical gradients

g

Center of gravity height difference is

UCN gas Mercury gasSame precession chamber


Gradient control: Cs magnetometers


Gravitational effect measured at ILL

R depends on vertical gradients

B0 down

B0 up


Monitoring gradients


Summary:

Expect UCN at PSI during this fallGetting ready for new nEDM measurement 2011/12 aiming at 5 x 10-27 ecm sensitivityDesigning n2EDM experiment to improve sensitivity to 5 x 10-28 ecm (2012+)


Let´s meet again at this workshop:

Physics of fundamentalSymmetries and Interactions – PSI2010

October 11-14, 2010 at the Paul Scherrer Institut, CHThe focus is on physics at the low energy, high precision frontier and related topics.psi2010.web.psi.ch


0 20 40 60 80 1000

25

50

75

100

125

SC on depolarizer pol. foil (scaling)

UC

N d

ensi

ty [a

rb.u

.]

snapshot times [s]

Filling the nEDM chamber

G. Zsigmond


Leakage current monitor

Important systematic→ monitoring → pA meter on ground

10:58:05 11:10:05 11:22:05 11:34:05

-4

-2

0

2

I mea

sure

d[nA

]time [hh:mm:ss]

∆ I = ± 8 pA

P. Schmidt-Wellenburg

n2EDM concept• double chamber system,

vertical stack of cylindrical chambers

• co-magnetometer (Hg, Xe?, He?)• Cs magnetometer array (64, 128, ?)

also inbetween UCN and He-3• 2 large He-3 magnetometers with

He-3 read-out by CsM• B-field and gradient stabilization by CsM

• 5-6-layer mu-metal shield,conceptual design ongoing

• external stabilization as needed

• UCN polarized by SC polarizer• UCN spin analysis above detector,

eventually simultaneous analysis

•Flexible DAQ


Neutron-mercury clock comparisonApril 2008, 5 days of data. December 2008, 6 days of data.

Altarev et al, PRL 103 (2009)


extract Larmor frequency:

keep the phase at 0°

past: phase locked mode now: adjust frequency

with PID controlto keep phase at 0°

control of phase offset

Cs magnetometer

0LRF )

-arctan( Φ+

Γ=Φ ωω

FRAP: A. Weis, P. Knowles, et al.

pump/read light in

to photo diode

AM light for RF production


HV-compatible (scalar) module components

optocoupler

photodiode

capacitor

light out

rf in

light in

•400/800 micron multimode fibers Coutesy: A. Pazgalev


Ramsey method of Separated Oscillating Fields

4.

3.

2.

1.

Free precession...

Apply π/2 spin-flip pulse...

“Spin up”neutron...

Second π/2 spin-flip pulse

130 s

2 s

2 s


Ramsey resonance “2-slit” interference patternPhase gives freq offset from resonance

29.7 29.8 29.9 30.0 30.1

10000

12000

14000

16000

18000

20000

22000

24000

x

x

x = working pointsResonant freq.

x

x

Spi

n-U

p N

eutr

on C

ount

s

Applied Frequency (Hz)


Hg-199 co-magnetometer

[2]


Choice of the scintillators stack

54 %

GS3-GS3-GS10

80%72%Efficiency / single GS10

GS30-GS10GS3-GS10Stack composition

95%

GS30-GS20 (50 – 100 µm)

88%81%Efficiency / single GS20

GS30-GS20(100 – 100 µm)

GS3-GS20Stack composition

Tests performed at ILL on the PF2/TEST beam line

GS10: natural 6Li; GS20: enriched 6Li; GS3/GS30: depleted 6Li

Improved light collection due to molecular sticking (SESO)Selected stack: GS30 (50 µm) – GS20 (100 µm)12 stacks have been ordered from SESO (delivery 02/10)

GS3

GS20

T. Lefort et al.


Iron layer laying on scintillators

Switch box

Light guides(hollow or Plexiglas)

PM tubes

Glass tube (L~ 35 cm, Ø 80-72 mm)

with NiMo coating

RF coil

Based on previous experiments- Adiabatic spin flipper (ASF)

- RF coil - Gradient field (stray field)- Analyzing foil

Permanent magnets + yoke

Sequential spin analyzer : ASF + analyzing foil

Further investigations:- Single crystal iron foil

UCN detection system

T. Lefort et al.

search for an edm of the neutron at psig2pc1.bu.edu/lept10/kirch_leptonmoments_2010.pdfsearch for an...

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