E. Traykov

Bio: E. Traykov is an academic researcher from Katholieke Universiteit Leuven. The author has contributed to research in topics: Penning trap & WITCH experiment. The author has an hindex of 7, co-authored 11 publications receiving 155 citations.

Precision measurements of the $^{60}$Co $\beta$-asymmetry parameter in search for tensor currents in weak interactions

Abstract: The $\beta$-asymmetry parameter $\widetilde{A}$ for the Gamow-Teller decay of $^{60}$Co was measured by polarizing the radioactive nuclei with the brute force low-temperature nuclear-orientation method. The $^{60}$Co activity was cooled down to milliKelvin temperatures in a $^3$He-$^4$He dilution refrigerator in an external 13 T magnetic field. The $\beta$ particles were observed by a 500 ${\mu}m$ thick Si PIN diode operating at a temperature of about 10 K in a magnetic field of 0.6 T. Extensive GEANT4 Monte-Carlo simulations were performed to gain control over the systematic effects. Our result, $\widetilde{A} = -1.014(12)_{stat}(16)_{syst}$, is in agreement with the Standard-Model value of $-0.987(9)$, which includes recoil-order corrections that were addressed for the first time for this isotope. Further, it enables limits to be placed on possible tensor-type charged weak currents as well as other physics beyond the Standard Model.

β asymmetry parameter in the decay of 114In

Abstract: The {beta}-asymmetry parameter A-tilde for the pure Gamow-Teller decay of {sup 114}In is reported. The low-temperature nuclear orientation method was combined with a GEANT4-based simulation code allowing us, for the first time, to address in detail the effects of scattering and the magnetic field. The result, A-tilde=-0.994{+-}0.010{sub stat}{+-}0.010{sub syst}, constitutes the most accurate value for the asymmetry parameter of a nuclear {beta} transition to date. The value is in agreement with the Standard Model prediction of A-tilde=-1 and provides new limits on tensor-type charged weak currents.

Simbuca, using a graphics card to simulate Coulomb interactions in a penning trap

Abstract: In almost all cases, N-body simulations are limited by the computation time available. Coulomb interaction calculations scale with O ( N 2 ) with N the number of particles. Approximation methods exist already to reduce the computation time to O ( N log N ) , although calculating the interaction still dominates the total simulation time. We present Simbuca, a simulation package for thousands of ions moving in a Penning trap which will be applied for the WITCH experiment. Simbuca uses the output of the Cunbody-1 library, which calculates the gravitational interaction between entities on a graphics card, and adapts it for Coulomb calculations. Furthermore the program incorporates three realistic buffer gas models, the possibility of importing realistic electric and magnetic fieldmaps and different order integrators with adaptive step size and error control. The software is released under the GNU General Public License and free for use.

Performance of silicon PIN photodiodes at low temperatures and in high magnetic fields

Abstract: The performance of an Si p–i–n (PIN) diode (type Hamamatsu S3590-06) as an energy sensitive detector operating at cryogenic temperatures ( ∼ 10 K ) and in magnetic fields up to 11 T was investigated, using a 207Bi conversion electron source. It was found that the detector still performs well under these conditions, with small changes in the response function being observed in high magnetic fields, e.g. a 30–50% decrease in energy resolution. A Monte Carlo simulation with the GEANT4 toolkit showed that the observed effects are mainly due to the modified trajectories of the electrons due to the influence of the magnetic field, which changes the scattering conditions, rather than to intrinsic changes of the performance of the detector itself.

A GEANT4 Monte-Carlo simulation code for precision β spectroscopy

Abstract: The measurement of the β asymmetry parameter in nuclear β decay is a potentially very sensitive tool to search for non V – A components in the charge-changing weak interaction. To reach the required precision (percent level) all effects that modify the emission pattern of the β radiation, i.e. the geometry of the setup, the effect of the magnetic field on the trajectories of β particles as well as (back)scattering in the source, on the sample holder and on the detector, have to be correctly taken into account in the analysis of the data. A thorough study of these effects and a new method based on detailed GEANT4 Monte-Carlo simulations that was developed for this purpose is presented here. The code was developed for β asymmetry measurements by means of the Low Temperature Nuclear Orientation (LTNO) method, but can in principle be generalized to other experimental setups using other polarization techniques.

Phd by thesis

Abstract: Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Probing Novel Scalar and Tensor Interactions from (Ultra)Cold Neutrons to the LHC

Abstract: Scalar and tensor interactions were once competitors to the now well-established V A structure of the Standard Model weak interactions. We revisit these interactions and survey constraints from low-energy probes (neutron, nuclear, and pion decays) as well as collider searches. Currently, the most stringent limit on scalar and tensor interactions arise from 0 + ! 0 + nuclear decays and the radiative pion decay ! e , respectively. For the future, we

New physics searches in nuclear and neutron $\beta$ decay

Abstract: The status of tests of the standard electroweak model and of searches for new physics in allowed nuclear $\beta$ decay and neutron decay is reviewed including both theoretical and experimental developments. The sensitivity and complementarity of recent and ongoing experiments are discussed with emphasis on their potential to look for new physics. Measurements are interpreted using a model-independent effective field theory approach enabling to recast the outcome of the analysis in many specific new physics models. Special attention is given to the connection that this approach establishes with high-energy physics. A new global fit of available $\beta$-decay data is performed incorporating, for the first time in a consistent way, superallowed $0^+\to 0^+$ transitions, neutron decay and nuclear decays. The constraints on exotic scalar and tensor couplings involving left- or right-handed neutrinos are determined while a constraint on the pseudoscalar coupling from neutron decay data is obtained for the first time as well. The values of the vector and axial-vector couplings, which are associated within the standard model to $V_{ud}$ and $g_A$ respectively, are also updated. The ratio between the axial and vector couplings obtained from the fit under standard model assumptions is $C_A/C_V = -1.27510(66)$. The relevance of the various experimental inputs and error sources is critically discussed and the impact of ongoing measurements is studied. The complementarity of the obtained bounds with other low- and high-energy probes is presented including ongoing searches at the Large Hadron Collider.