arXiv subjects

Justas Zalieckas

Publications and source records attributed to Justas Zalieckas.

3 recordsLinked to original sources

arXiv2026

Multiparametric Quantum Sensing of Liquids Using NV Centres and Tethered Magnetic Nanoparticles

We propose a new concept for non-invasive, multiparametric liquid analysis based on nitrogen-vacancy (NV) centre magnetometry, relaxometry and surface-tethered magnetic nanoparticles. Magnetic nanoparticles are anchored to a diamond surface via DNA strands, forming nanoscale mechanical oscillators whose thermally driven motion is strongly influenced by the surrounding liquid environment. The resulting time-dependent magnetic fields couple to near-surface NV centres and are detected via optically detected magnetic resonance or changes in spin coherence time. By spatially patterning the diamond surface with regions functionalised by DNA tethers of different lengths, sequences, or chemical modifications, a single liquid is mapped onto a high-dimensional quantum response vector rather than a single scalar observable. Changes in viscosity, molecular adsorption, or chemical interactions modify the dynamics of magnetic nanoparticles in a region-specific manner, enabling differential sensing across the surface. We outline the physical transduction mechanism, discuss relevant scaling relations, and assess experimental feasibility using established wide-field NV magnetometry and relaxometry methods. The proposed platform combines quantum sensing with surface heterogeneity, offering a versatile route toward parallel, label-free liquid characterisation.

cond-mat.mes-hall↗

arXiv2016

SiPM Gain Stabilization Studies for Adaptive Power Supply

We present herein gain stabilization studies of SiPMs using a climate chamber at CERN. We present results for four detectors not tested before, three from Hamamatsu and one from KETEK. Two of the Hamamatsu SiPMs are novel sensors with trenches that reduce cross talk. We use an improved readout system with a digital oscilloscope controlled with a dedicated LabView program. We improved and automized the analysis to deal with large datasets. We have measured the gain-versus-bias-voltage dependence at fixed temperature and gain-versus-temperature dependence at fixed bias voltage to determine the bias voltage dependence on temperature $V(T)$ for stable gain. We show that the gain remains stable to better than $\pm 0.5\%$ in the $20^\circ \rm C - 30^\circ C$ temperature range if the bias voltage is properly adjusted with temperature.

physics.ins-det↗

arXiv2014

Gain Stabilization of SiPMs

The gain of SiPMs depends both on bias voltage and on temperature. For stable operations, both need to be kept constant. In an ILC calorimeter with millions of channels, this is a challenging task. It is, therefore, desirable to compensate for temperature variations by automatically readjusting the bias voltage. We have designed a bias voltage regulator board to achieve this task. We anticipate an uncertainty on the gain stability at the level of $< 1\%$. First, we present measurements of the gain dependence on temperature and bias voltage for several SiPMs from three different manufacturers and determine their dV/dT dependence. Next, we demonstrate the performance of the gain stability with the bias voltage regulator test board on four SiPMs.

physics.ins-det↗