WITCH: Testing the Standard Model using a betarecoil spectrometer with a trapped ion cloud as source

1
WITCH Testing the Standard Model using a
beta-recoil spectrometer with a trapped ion cloud
as source
  A. Lindroth1, F. Ames2, D. Beck1, M. Beck1, G.
Bollen3, B. Delauré1, J. Deutsch4, V.V. Golovko1,
V. Yu. Kozlov1, I. Kraev1, T. Phalet1, K.
Reisinger2, P. Schuurmans1, N. Severijns1, S.
Versyck1. 1Instituut for Kern- en
Stralingsfysica, K. U. Leuven, Celesijnenlaan
200D, B-3001 Leuven, Belgium 2LMU, München,
Germany 3MSU, East Lansing, MI,
USA 4Louvain-la-Neuve, Belgium Email 
Axel.Lindroth_at_fys.kuleuven.ac.be
Weak Interaction Trap for Charged Particles

• CONTENTS OF THIS TALK
• Weak Interaction Motivation
• The Set-Up
• Using the Set-Up
• Other Possible Experiments with WITCH

2
Scalar contributions to pure Fermi decays

• Johnson et al 6He GT? A/T
• Adelberger et al 32Ar F? V/S
• Allen et al 6He, 19Ne, 23Ne, 35Ar F GT

3
Nuclear recoil measurements of a
4
Overview of the WITCH set-up
5
The System of 2 Traps
6
The Trap Structure
Magnetron Motion
Cyclotron Motion
Axial Motion
7
The Retardation Spectrometer
8
Set-up Behavior Measurement
46V (a1.0)
35Ar (a0.908)
Retardation Voltage
9
Precision of S measurement with WITCH

• We need 107 events in the differential recoil
  spectrum.
• 4 days measurement time needed!
• From this we should get Da/a0.5 at 1s.

107
106
105
Events in continuous spectrum for different
fitting intervals.
10
A General b-recoil Spectrometer
T interaction F/GT ratios Measure excited states
Q values Charge state distributions EC/b
ratios Polarized Nuclei In-trap spectroscopy
1 e5
EC
80000
60000
1
Intensity events
2
40000
3
20000
0
0
100
200
300
400
Retardation Voltage