First detection and energy measurement of recoil ions following beta decay in a Penning trap with the WITCH experiment

Abstract

Abstract. The WITCH experiment (Weak Interaction Trap for CHarged particles) will search for exotic interactions by investigating the β-ν angular correlation via the measurement of the recoil energy spectrum after β decay. As a first step the recoil ions from the β − decay of 124 In stored in a Penning trap have been detected. The evidence for the detection of recoil ions is shown and the properties of the ion cloud that forms the radioactive source for the experiment in the Penning trap are presented.PACS. 23.40.Bw Weak-interaction and lepton (including neutrino) aspects -29.30.Aj Charged-particle spectrometers: electric and magnetic -37.10.Ty ion trapping

Prospects for precision measurements in nuclear decay in the LHC era

“…The detection of positively charged recoil ions from singly charged trapped ions relies on the single or multiple shake-off process of the bound electrons. A first measurement of a recoil spectrum from stored 124 In + ions has been reported [72]. The precision goal of this experiment is to reach the level of δa…”

Measurement of theβ-asymmetry parameter ofCu67in search for tensor-type currents in the weak interaction

“…[3]). Many recent experimental efforts try to improve the sensitivity to these non-standard model weak currents in searches for differences of experimental observables from their standard model predictions in both neutron decay [4][5][6][7][8][9][10] and nuclear β decay [2,[11][12][13][14][15][16][17][18].…”

Magnetic guidance of charged particles

“…In many experiments the field decreases continuously from B at the source to B' at the detector, which avoids glancing incidence on the detector for particles emitted near θ = /2. In the experiments [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] cited in the introduction, non-adiabatic transitions are strictly suppressed because their angle dependent energy losses would corrupt the measurements. In the adiabatic approximation, for BB   the inverse magnetic mirror effect makes the gyration radius widen from r at the source to r' on the detector, while the helix angle decreases from  to ', with…”

“…In more recent times, magnetic fields are increasingly being used to simply guide charged particles, like electrons, muons, ions, or other, efficiently from a source to a detector. Such setups are found in magnetic photoelectron imaging [6,7,8], invented in the early 1980ies, molecular reaction microscopes [9,10] (early nineties), retardation spectrometers [11,12,13] (early nineties), time projection chambers [14] (mid-seventies), and in muon [15], neutron [16,17], or nuclear decay [18] spectrometers, to name just a few experiments and surveys. In these applications charged particles are emitted over a wide range of emission angles (0 < θ  /2), and the number of orbits of gyration may vary widely (0 < n < ).…”

“…new PSF f(x,y), calculated directly from Eq. (15) with(18) and(25) for n0 = 1.6. Strong resonances are seen whenever R falls onto one of the maxima Rn inFig.…”