the witch experiment: campaign 2006 and perspectives
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The WITCH experiment: campaign 2006 and perspectives. Valentin Kozlov on behalf of the WITCH team: - PowerPoint PPT PresentationTRANSCRIPT
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
12-February-2007 Weak Interaction Trap for CHarged particles
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Outline
Experiment / Setup
Present status
Results of 2006
Future possibilities
Conclusion
12-February-2007 Weak Interaction Trap for CHarged particles
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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)
12-February-2007 Weak Interaction Trap for CHarged particles
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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
;=
12-February-2007 Weak Interaction Trap for CHarged particles
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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
12-February-2007 Weak Interaction Trap for CHarged particles
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November’06 124In: On/Off
12-February-2007 Weak Interaction Trap for CHarged particles
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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
12-February-2007 Weak Interaction Trap for CHarged particles
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offline measurement
60Co activity = 11kBq
Tmeas (eff.) = 10000 cycles x 2.3 s or 2.3e+4 s
12-February-2007 Weak Interaction Trap for CHarged particles
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offline measurement
90Sr activity ~ 40kBq
Tmeas (eff.) = 700 cycles x 2.3 s or 1610 s
12-February-2007 Weak Interaction Trap for CHarged particles
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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
12-February-2007 Weak Interaction Trap for CHarged particles
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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