The half-life of $^6$He has been measured using a low-energy radioactive beam implanted in an YAlO$_3$ Ce-doped inorganic scintillator and recording decay events in a 4π geometry. Events were ...time-stamped with a digital data acquisition system enabling a reliable control of dead-time effects and detector gain variations. The result, T$_{1/2}$ = (807.25 ± 0.16$_{stat}$ ± 0.11$_{sys}$) ms, provides the most precise value obtained so far and is consistent with the only previous measurement having a precision smaller than 0.1%. This resolves the long-standing discrepancy previously observed between two sets of measurements.
A trap system has been built to perform high-precision
β
-decay experiments. The system is coupled to the low-energy beam line of the SPIRAL source at GANIL. The continuous ion beam from SPIRAL with ...energies between 10 and 20
keV is slowed down by means of a buffer-gas-filled RFQ trap and ejected thereafter as short ion bunches into a novel transparent Paul trap. Two pulsed cavities located downstream from the RFQ reduce the energy of the ion bunch down to about a hundred eV for an efficient capture in the Paul trap. We describe here the complete system along with the first results obtained with stable
He
+
4
,
Cl
+
35
and
Ar
+
36
,
40
ions from the SPIRAL ECR source. An overall efficiency of
8.7
(
8
)
×
10
-
4
is achieved for
4
He
+
ions under specific conditions.
The experimental achievements and the current program with the LPCTrap device installed at the LIRAT beam line of the SPIRAL1‐GANIL facility are presented. The device is dedicated to the study of the ...weak interaction at low energy by means of precise measurements of the β−ν angular correlation parameter. Technical aspects as well as the main results are reviewed. The future program with new available beams is briefly discussed.
The experimental achievements and the current program with the LPCTrap device installed at the LIRAT beam line of the SPIRAL1‐GANIL facility are presented. The device is dedicated to the study of the weak interaction at low energy by means of precise measurements of the β−ν angular correlation parameter. Technical aspects as well as the main results are reviewed. The future program with new available beams is briefly discussed.
Measurement of the F 20 half-life Hughes, M.; George, E. A.; Naviliat-Cuncic, O. ...
Physical review. C,
05/2018, Letnik:
97, Številka:
5
Journal Article
The existence of a mirror world holding a copy of our ordinary particle spectrum could lead to oscillations between the neutron (n) and its mirror partner (
n
′
). Such oscillations could manifest ...themselves in storage experiments with ultracold neutrons whose storage lifetime would depend on the applied magnetic field. Here, extended details and measurements from the first dedicated experimental search for
nn
′
oscillations published in G. Ban, K. Bodek, M. Daum, R. Henneck, S. Heule, M. Kasprzak, N. Khomutov, K. Kirch, S. Kistryn, A. Knecht, P. Knowles, M. Kuźniak, T. Lefort, A. Mtchedlishvili, O. Naviliat-Cuncic, C. Plonka, G. Quéméner, M. Rebetez, D. Rebreyend, S. Roccia, G. Rogel, M. Tur, A. Weis, J. Zejma, G. Zsigmond, Direct experimental limit on neutron mirror–neutron oscillations, Phys. Rev. Lett. 99 (2007) 161603 will be presented, focussing on a possible dependence of the UCN counts on the magnetic field and its direction. However, at present no significant change in the averaged UCN counts with respect to the applied magnetic field has been found.
We present the new spectrometer for the neutron electric dipole moment (nEDM) search at the Paul Scherrer Institute (PSI), called n2EDM. The setup is at room temperature in vacuum using ultracold ...neutrons. n2EDM features a large UCN double storage chamber design with neutron transport adapted to the PSI UCN source. The design builds on experience gained from the previous apparatus operated at PSI until 2017. An order of magnitude increase in sensitivity is calculated for the new baseline setup based on scalable results from the previous apparatus, and the UCN source performance achieved in 2016.
First results are presented from an experiment that aims at the simultaneous determination of both transversal polarization components of electrons emitted in the decay of free neutrons—two ...observables that have never before been addressed experimentally. A non-zero value of the
R correlation coefficient, due to the
e
-
polarization component perpendicular to the plane spanned by the spin of the decaying neutron and the electron momentum, would signal a violation of time reversal invariance. The value of the
N correlation coefficient, given by the transverse
e
-
polarization component within that plane, is expected to be finite. The measurement of
N, both, probes the Standard Model and serves as an important systematic check of the experimental apparatus with respect to the
R correlation measurement. Data taking using the polarized cold neutron beam FUNSPIN from the SINQ spallation source at the Paul Scherrer Institute, Villigen, Switzerland, has been completed. Preliminary results of the data analysis are presented. Two options for a possible future experiment leading to the accuracy of about
3
×
10
-
4
are discussed.
High-precision searches for an electric dipole moment of the neutron (nEDM) require stable and uniform magnetic field environments. We present the recent achievements of degaussing and equilibrating ...the magnetically shielded room (MSR) for the n2EDM experiment at the Paul Scherrer Institute. We present the final degaussing configuration that will be used for n2EDM after numerous studies. The optimized procedure results in a residual magnetic field that has been reduced by a factor of two. The ultra-low field is achieved with the full magnetic-field-coil system, and a large vacuum vessel installed, both in the MSR. In the inner volume of
∼
1.4
m
3
, the field is now more uniform and below 300 pT. In addition, the procedure is faster and dissipates less heat into the magnetic environment, which in turn, reduces its thermal relaxation time from
12
h
down to
1.5
h
.
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