The WITCH experiment: campaign 2006 and perspectives

12-February-2007 Weak Interaction Trap for CHarged particles

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INSTITUUT VOOR KERN- EN STRALINGSFYSICA

The WITCH experiment:

campaign 2006 and perspectives

Valentin Kozlovon behalf of the WITCH team:

S. Coeck 1), M. Herbane 1), V. Kozlov 1), N. Severijns 1), M. Tandecki 1), M. Beck 2), P. Friedag 2), P. Delahaye 3), A. Herlert 3), F. Wenander 3) ,

D. Záckouký 4)

1) IKS K.U.Leuven, 2) IKP Uni Muenster, 3) CERN, 4) NPI ASCR (Prague)

ISOLDE Workshop, 12-14 February 2007


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Outline

Experiment / Setup

Present status

Results of 2006

Future possibilities

Conclusion


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Primary goalWeak Interactions of -decay:

0'' TTSS CCCCStandard Model: V-A interaction

0.06S

V

CC 1)0.8T

A

CC 1)

int 5

5

12 5

5 5

5 5

( )( )

( )( )

( )( )

( )( )

( )( ) . .

p n e e

p n e e

p n e e

p n e e

p n e e

S S

V V

T T

A A

P P

C C

C C

C C

c

C

C

H

C

C h

?

?

1) N. Severijns, M. Beck, O. Naviliat-Cuncic, Rev. Mod. Phys. 78 (2006)

95% C.L.

(S)

(V)

(T)

(A)

(P)


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Physics principle

2 2 2 2

2 2 2 2V V S S

Fermi

V V S S

C C C Ca

C C C C

- angular correlation:

Scalar1a

Vector1a

5004003002001000

1

0.8

0.6

0.4

0.2

Recoil energy (eV)

+

e

Vector

Scalar

+

e

( ) 1 cos( )v

W ac

;=


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Experimental set-up

90 bender

Energy analysis by retardation

Einzellens

Post acceleration

B [T]Uret [V]


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EfficienciesBest achieved

Description ‘ideal set-up’ 2004 - 2006

Beamline transfer + pulse-down 50% 0%

Injection into B-field, injection 100% 20%

Cooler trap efficiency 100% 60%

Transfer between traps 100% 80%Storage in the decay trap 100% 100%

Fraction of ions leaving the decay trap ~40% not studied

Shake-off for charge state n=1, p(n=1) 10% not studied

Transmission through spectrometer 100% 0% (prelim.)

MCP efficiency, MCP 60% 52.3(3)% a)

Total efficiency 1% c) 0.15% b), c) a) Lienard et al., NIM A 551 (2005) 375. b) improved up to factor of 200 in comparison with 2004 c) for decay these numbers are about 10 times larger


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November’06 124In: On/Off


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Prelim

inary!

Preliminary!

1+: 0.1, 2+: 0.74, 3+: 0.12, 80% 124mIn + 20% 124gIn

Trap load: 1e+5 ions

Tmeas (eff.) = 500 cycles x 2.3 s or 1150 s

November’06: 124In recoil spectrum

124gIn:

Rend= 196 eV

124mIn:

Rend= 83 eV


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offline measurement

60Co activity = 11kBq

Tmeas (eff.) = 10000 cycles x 2.3 s or 2.3e+4 s


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offline measurement

90Sr activity ~ 40kBq

Tmeas (eff.) = 700 cycles x 2.3 s or 1610 s


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Pulse-height-distributions (PHD)

Retardation is OFF

QDC channel (a.u.)

Retardation is ON

QDC channel (a.u.)

Courtesy of M.Beck


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In-trap -detector

Cooler trap Decay trap

He-inlet

Pumping diaphragm

to be changed by scintillator

To have normalization between different trap loads To have start signal for TOF measurement To evaluate -background on the main detector on-line …?


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More physics

Tensor interactions F/GT mixing ratio EC/+ ratio Charge state distribution Search for heavy neutrinos

(kinks in the recoil spectrum) Precise spectrum shape measurement

…?


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Conclusion

Primary goal is to probe the Standard Model

for Scalar admixture

WITCH set-up is operational

Efficiency of the set-up was improved by factor of 200

First recoil ion spectrum is observed!

Plan 2007: improve the accuracy of measurement

We are looking to extend our physics program and

are open for any interesting suggestions!


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124In isotope data

124gIn: http://ie.lbl.gov/toi/nuclide.asp?iZA=490124

124mIn: http://ie.lbl.gov/toi/nuclide.asp?iZA=490424

http://ie.lbl.gov/toi/nuclide.asp?iZA=490124

http://ie.lbl.gov/toi/nuclide.asp?iZA=490424

The WITCH experiment: campaign 2006 and perspectives

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