arXiv subjects

Andrei Puiu

Publications and source records attributed to Andrei Puiu.

6 recordsLinked to original sources

arXiv2026

Prospects for precision CE$\nu$NS measurements with electron-capture neutrinos and lithium-based bolometers

We evaluate the feasibility of high-precision coherent elastic neutrino-nucleus scattering measurements exploiting mono-energetic neutrinos produced by electron-capture (EC) decays of intense radioactive sources, such as $^{51}$Cr or $^{37}$Ar. To fully exploit the high neutrino flux achievable with EC sources, and accounting for the low energy of EC neutrinos, we evaluate the sensitivity of a compact array of bolometric detectors with absorbers based on light elements, such as lithium, oxygen and fluorine. With 1 kg of LiF detectors, source activities of $\sim10^{17}$ Bq, and assuming an energy threshold of 20 eV, we expect to achieve a $\sim 3\%$ precision on the determination of the neutrino flux with 90 days of measurement. Such a measurement would represent a test of the gallium neutrino anomaly, and could disentangle nuclear effects on gallium from the misevaluation of the EC source activity or short-baseline neutrino oscillations.

hep-ph↗

arXiv2024

Deep learning-based identification of patients at increased risk of cancer using routine laboratory markers

Early screening for cancer has proven to improve the survival rate and spare patients from intensive and costly treatments due to late diagnosis. Cancer screening in the healthy population involves an initial risk stratification step to determine the screening method and frequency, primarily to optimize resource allocation by targeting screening towards individuals who draw most benefit. For most screening programs, age and clinical risk factors such as family history are part of the initial risk stratification algorithm. In this paper, we focus on developing a blood marker-based risk stratification approach, which could be used to identify patients with elevated cancer risk to be encouraged for taking a diagnostic test or participate in a screening program. We demonstrate that the combination of simple, widely available blood tests, such as complete blood count and complete metabolic panel, could potentially be used to identify patients at risk for colorectal, liver, and lung cancers with areas under the ROC curve of 0.76, 0.85, 0.78, respectively. Furthermore, we hypothesize that such an approach could not only be used as pre-screening risk assessment for individuals but also as population health management tool, for example to better interrogate the cancer risk in certain sub-populations.

cs.LG↗

arXiv2024

Evaluating radiation impact on transmon qubits in above and underground facilities

Superconducting qubits can be sensitive to abrupt energy deposits caused by cosmic rays and ambient radioactivity. While previous studies have explored correlated effects in time and space due to cosmic ray interactions, we present the first direct comparison of a transmon qubit's performance measured at two distinct sites: the above-ground SQMS facility (Fermilab, US) and the deep-underground Gran Sasso Laboratory (Italy). Despite the stark difference in radiation levels, we observe a similar average qubit relaxation time of approximately 80 microseconds at both locations. To further investigate potential radiation-induced events, we employ a fast decay detection protocol, comparing the relative rates of triggered events between the two environments. Although intrinsic noise remains the dominant source of single errors in superconducting qubits, our analysis revealed a significant excess of radiation-induced events for high-coherence transmon qubits operated above-ground. Finally, using $\gamma$-ray sources with increasing activity levels, we evaluate the qubit response in a controlled low-background environment.

quant-ph↗

arXiv2023

LUCE: A milli-Kelvin calorimeter experiment to study the electron capture of 176Lu

The LUCE (LUtetium sCintillation Experiment) project will search for the 176Lu electron capture based on a milli-Kelvin calorimetric approach. This decay is of special interest in the field of nuclear structure, with implications for the s-process and for a better comprehension of the nuclear matrix elements of neutrinoless double beta decay (0{\nu}\b{eta}\b{eta}) and two-neutrino double beta decay (2{\nu}\b{eta}\b{eta}). Possible impacts also include the development of a new class of coherent elastic neutrino-nucleus scattering (CE{\nu}NS) and spin-dependent (independent) dark matter detectors. We report on the current status and design of a novel detector cryogenic-module for the measurement of the electron capture and detail a future measurement plan.

physics.ins-det↗

arXiv2018

Deep Neural Networks for ECG-free Cardiac Phase and End-Diastolic Frame Detection on Coronary Angiographies

Invasive coronary angiography (ICA) is the gold standard in Coronary Artery Disease (CAD) imaging. Detection of the end-diastolic frame (EDF) and, in general, cardiac phase detection on each temporal frame of a coronary angiography acquisition is of significant importance for the anatomical and non-invasive functional assessment of CAD. This task is generally performed via manual frame selection or semi-automated selection based on simultaneously acquired ECG signals - thus introducing the requirement of simultaneous ECG recordings. We evaluate the performance of a purely image based workflow based on deep neural networks for fully automated cardiac phase and EDF detection on coronary angiographies. A first deep neural network (DNN), trained to detect coronary arteries, is employed to preselect a subset of frames in which coronary arteries are well visible. A second DNN predicts cardiac phase labels for each frame. Only in the training and evaluation phases for the second DNN, ECG signals are used to provide ground truth labels for each angiographic frame. The networks were trained on 17800 coronary angiographies from 3900 patients and evaluated on 27900 coronary angiographies from 6250 patients. No exclusion criteria related to patient state, previous interventions, or pathology were formulated. Cardiac phase detection had an accuracy of 97.6%, a sensitivity of 97.6% and a specificity of 97.5% on the evaluation set. EDF prediction had a precision of 97.4% and a recall of 96.9%. Several sub-group analyses were performed, indicating that the cardiac phase detection performance is largely independent from acquisition angles and the heart rate of the patient. The average execution time of cardiac phase detection for one angiographic series was on average less than five seconds on a standard workstation.

cs.CV↗

arXiv2017

Electron-phonon coupling in Ti/TiN MKIDs multilayer microresonator

Over the last few years there has been a growing interest toward the use of superconducting microwave microresonators operated in quasi-thermal equilibrium mode, especially applied to single particle detection. Indeed, previous devices designed and tested by our group with X-ray sources in the keV range evidenced that several issues arise from the attempt of detection through athermal quasiparticles produced within direct strikes of X-rays in the superconductor material of the resonator. In order to prevent issues related to quasiparticles self-recombination and to avoid exchange of athermal phonons with the substrate, our group focused on the development of thermal superconducting microresonators. In this configuration resonators composed of multilayer films of Ti/TiN sense the temperature of an absorbing material. To maximize the thermal response, low critical temperature films are preferable. By lowering the critical temperature, though, the maximum probing power bearable by the resonators decrease abruptly because of the weakening of the electron-phonon coupling. A proper compromise has to be found in order to avoid signal to noise ratio degradation. In this contribution we report the latest measurement of the electron-phonon coupling.

physics.ins-det↗