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A. Stahl

Publications and source records attributed to A. Stahl.

At least 19 recordsLinked to original sources
arXiv2025

First Measurement of Neutrino Emissions from Spent Nuclear Fuel by the Double Chooz Experiment

Neutrino emission from nuclear reactors provides real-time insights into reactor power and fuel evolution, with potential applications in monitoring and nuclear safeguards. Following reactor shutdown, a low-intensity flux of ``residual neutrinos'' persists due to the decay of long-lived fission isotopes in the partially burnt fuel remaining within the reactor cores and in spent nuclear fuel stored in nearby cooling pools. The Double Chooz experiment at the Chooz B nuclear power plant in France achieved the first quantitative measurement of this residual flux based on 17.2 days of reactor-off data. In the energy range where the residual signal is most pronounced, the neutrino detector located 400$\,$m from the cores recorded $106 \pm 18$ neutrino candidate events (5.9$σ$ significance). This measurement is in excellent agreement with the predicted value of $88 \pm 7$ events derived from detailed reactor simulations modeling the decay activities of fission products and incorporating the best-available models of neutrino spectra.

hep-ex↗
arXiv2023

Comparison of readout systems for high-rate silicon photo-multiplier applications

Recent years have shown an increased use of silicon photo-multipliers (SiPM) in experiments as they are of reasonable cost, have relatively low power consumption and are easily available in a variety of form factors allowing for a large number of readout channels. At the same time, experiments are generating data at increasingly high rates requiring the use of more efficient readout systems. In this work, the dead time, efficiency, dynamic range, coincidence time resolution and energy resolution of five different readout systems at various stages of maturity are evaluated to determine the best system for acquiring data from a detector in a high rate experiment. Additional functionalities of the systems are also discussed.

physics.ins-det↗
arXiv2023

Magnetic shielding for large photoelectron multipliers for the OSIRIS facility of the JUNO detector

We present the technical design and characteristics of the magnetic shield developed for 20" PMTs of the low-background OSIRIS facility. A ribbon of amorphous alloy with the extreme magnetic permeability was used in its design providing the excellent efficiency in screening the Earth's magnetic field with a relatively small amount of the material. The mass of materials is crucial for the construction of low-background facilities from the point of view of radioactive backgrounds. Using amorphous materials is cost-efficient compared to other methods for screening the Earth's magnetic field.

physics.ins-det↗
arXiv2022

E-TEST prototype design report

E-TEST (Einstein Telescope Euregio-Meuse-Rhin Site and Technology) is a project recently funded by the European program Ineterreg Euregio Meuse-Rhine. This program is dedicated to innovative cross boarder activities between Belgium, The Netherlands and Germany. With a total budget of15MC and a consortium of 11 partners from the three countries, the objective of the project is twofold. Firstly, to develop an eco-friendly and non-invasive imaging of the geological conditions as well as the development of an observatory of the underground in the EMR region. Secondly, to develop technologies necessary for 3rd generation gravitational wave detectors. In particular, it is proposed to develop a prototype of large suspended cryogenic silicon mirror, isolated from seismic vibrations at low frequency. The total budget of the project is equally spread over the two activities. The first activity is not discussed at all in this report. The E-TEST prototype will have some key unique features: a silicon mirror of 100 kg, a radiative cooling strategy (non contact), a low-frequency hybrid isolation stage, cryogenic sensors and electronics, a laser and optics at 2 microns, a low thermal noise coating.

astro-ph.IM↗
arXiv2022

Partition Pooling for Convolutional Graph Network Applications in Particle Physics

Convolutional graph networks are used in particle physics for effective event reconstructions and classifications. However, their performances can be limited by the considerable amount of sensors used in modern particle detectors if applied to sensor-level data. We present a pooling scheme that uses partitioning to create pooling kernels on graphs, similar to pooling on images. Partition pooling can be used to adopt successful image recognition architectures for graph neural network applications in particle physics. The reduced computational resources allow for deeper networks and more extensive hyperparameter optimizations. To show its applicability, we construct a convolutional graph network with partition pooling that reconstructs simulated interaction vertices for an idealized neutrino detector. The pooling network yields improved performance and is less susceptible to overfitting than a similar network without pooling. The lower resource requirements allow the construction of a deeper network with further improved performance.

hep-ex↗
arXiv2022

ETpathfinder: a cryogenic testbed for interferometric gravitational-wave detectors

The third-generation of gravitational wave observatories, such as the Einstein Telescope (ET) and Cosmic Explorer (CE), aim for an improvement in sensitivity of at least a factor of ten over a wide frequency range compared to the current advanced detectors. In order to inform the design of the third-generation detectors and to develop and qualify their subsystems, dedicated test facilities are required. ETpathfinder prototype uses full interferometer configurations and aims to provide a high sensitivity facility in a similar environment as ET. Along with the interferometry at 1550 nm and silicon test masses, ETpathfinder will focus on cryogenic technologies, lasers and optics at 2090 nm and advanced quantum-noise reduction schemes. This paper analyses the underpinning noise contributions and combines them into full noise budgets of the two initially targeted configurations: 1) operating with 1550 nm laser light and at a temperature of 18 K and 2) operating at 2090 nm wavelength and a temperature of 123 K.

astro-ph.IM↗
arXiv2021

Search for Signatures of Sterile Neutrinos with Double Chooz

We present a search for signatures of neutrino mixing of electron anti-neutrinos with additional hypothetical sterile neutrino flavors using the Double Chooz experiment. The search is based on data from 5 years of operation of Double Chooz, including 2 years in the two-detector configuration. The analysis is based on a profile likelihood, i.e.\ comparing the data to the model prediction of disappearance in a data-to-data comparison of the two respective detectors. The analysis is optimized for a model of three active and one sterile neutrino. It is sensitive in the typical mass range $5 \cdot 10^{-3} $ eV$^2 \lesssim Δm^2_{41} \lesssim 3\cdot 10^{-1} $ eV$^2$ for mixing angles down to $\sin^2 2θ_{14} \gtrsim 0.02$. No significant disappearance additionally to the conventional disappearance related to $θ_{13} $ is observed and correspondingly exclusion bounds on the sterile mixing parameter $θ_{14} $ as function of $ Δm^2_{41} $ are obtained.

hep-ex↗
arXiv2021

Storage Ring to Search for Electric Dipole Moments of Charged Particles -- Feasibility Study

The proposed method exploits charged particles confined as a storage ring beam (proton, deuteron, possibly $^3$He) to search for an intrinsic electric dipole moment (EDM) aligned along the particle spin axis. Statistical sensitivities could approach 10$^{-29}$ e$\cdot$cm. The challenge will be to reduce systematic errors to similar levels. The ring will be adjusted to preserve the spin polarisation, initially parallel to the particle velocity, for times in excess of 15 minutes. Large radial electric fields, acting through the EDM, will rotate the polarisation from the longitudinal to the vertical direction. The slow rise in the vertical polarisation component, detected through scattering from a target, signals the EDM. The project strategy is outlined. A stepwise plan is foreseen, starting with ongoing COSY activities that demonstrate technical feasibility. Achievements to date include reduced polarization measurement errors, long horizontal plane polarization lifetimes, and control of the polarization direction through feedback from scattering measurements. The project continues with a proof-of-capability measurement (precursor experiment; first direct deuteron EDM measurement), an intermediate prototype ring (proof-of-principle; demonstrator for key technologies), and finally a high-precision electric-field storage ring.

hep-ex↗
arXiv2021

Theia: An advanced optical neutrino detector

New developments in liquid scintillators, high-efficiency, fast photon detectors, and chromatic photon sorting have opened up the possibility for building a large-scale detector that can discriminate between Cherenkov and scintillation signals. Such a detector could exploit these two distinct signals to observe particle direction and species using Cherenkov light while also having the excellent energy resolution and low threshold of a scintillator detector. Situated in a deep underground laboratory, and utilizing new techniques in computing and reconstruction techniques, such a detector could achieve unprecedented levels of background rejection, thus enabling a rich physics program that would span topics in nuclear, high-energy, and astrophysics, and across a dynamic range from hundreds of keV to many GeV. The scientific program would include observations of low- and high-energy solar neutrinos, determination of neutrino mass ordering and measurement of the neutrino CP violating phase, observations of diffuse supernova neutrinos and neutrinos from a supernova burst, sensitive searches for nucleon decay and, ultimately, a search for NeutrinoLess Double Beta Decay (NLDBD) with sensitivity reaching the normal ordering regime of neutrino mass phase space. This paper describes Theia, a detector design that incorporates these new technologies in a practical and affordable way to accomplish the science goals described above. We consider two scenarios, one in which Theia would reside in a cavern the size and shape of the caverns intended to be excavated for the Deep Underground Neutrino Experiment (DUNE) which we call Theia 25, and a larger 100 ktonne version (Theia 100) that could achieve an even broader and more sensitive scientific program.

physics.ins-det↗
arXiv2020

Beam-based alignment at the Cooler Synchrotron COSY as a prerequisite for an electric dipole moment measurement

The Jülich Electric Dipole moment Investigation (JEDI) collaboration aims at a direct measurement of the Electric Dipole Moment (EDM) of protons and deuterons using a storage ring. The measurement is based on a polarization measurement. In order to reach highest accuracy, one has to know the exact trajectory through the magnets, especially the quadrupoles, to avoid the influence of magnetic fields on the polarization vector. In this paper, the development of a beam-based alignment technique is described that was developed and implemented at the COoler SYnchrotron (COSY) at Forschungszentrum Jülich. Well aligned quadrupoles permit one to absolutely calibrate the Beam Position Monitors (BPMs). The method is based on the fact that a particle beam, which does not pass through the center of a quadrupole, experiences a deflection. The precision reached by the method is approximately 40 micro meter. Some consequences for the design of a new high precision storage ring for EDM mesasurements are discussed.

physics.acc-ph↗
arXiv2020

Reactor Rate Modulation oscillation analysis with two detectors in Double Chooz

A $θ_{13}$ oscillation analysis based on the observed antineutrino rates at the Double Chooz far and near detectors for different reactor power conditions is presented. This approach provides a so far unique simultaneous determination of $θ_{13}$ and the total background rates without relying on any assumptions on the specific background contributions. The analysis comprises 865 days of data collected in both detectors with at least one reactor in operation. The oscillation results are enhanced by the use of 24.06 days (12.74 days) of reactor-off data in the far (near) detector. The analysis considers the \nue interactions up to a visible energy of 8.5 MeV, using the events at higher energies to build a cosmogenic background model considering fast-neutrons interactions and $^{9}$Li decays. The background-model-independent determination of the mixing angle yields sin$^2(2θ_{13})=0.094\pm0.017$, being the best-fit total background rates fully consistent with the cosmogenic background model. A second oscillation analysis is also performed constraining the total background rates to the cosmogenic background estimates. While the central value is not significantly modified due to the consistency between the reactor-off data and the background estimates, the addition of the background model reduces the uncertainty on $θ_{13}$ to 0.015. Along with the oscillation results, the normalization of the anti-neutrino rate is measured with a precision of 0.86\%, reducing the 1.43\% uncertainty associated to the expectation.

hep-ex↗
arXiv2020

Measurement of deuteron carbon vector analyzing powers in the kinetic energy range 170-380 MeV

A measurement of vector analyzing powers in elastic deuteron-carbon scattering has been performed at the Cooler Synchrotron COSY of Forschungszentrum Jülich, Germany. Seven kinetic beam energies between 170 and 380 MeV have been used. A vector-polarized beam from a polarized deuteron source was injected, accelerated to the final desired energy and stored in COSY. A thin needle-shaped diamond strip was used as a carbon target, onto which the beam was slowly steered. Elastically scattered deuterons were identified in the forward direction using various layers of scintillators and straw tubes. Where data exist in the literature (at 200 and 270 MeV), excellent agreement of the angular shape was found. The beam polarization of the presented data was deduced by fitting the absolute scale of the analyzing power to these references. Our results extend the world data set and are necessary for polarimetry of future electric dipole moment searches at storage rings. They will as well serve as an input for theoretical description of polarized hadron-hadron scattering.

nucl-ex↗
arXiv2020

Cryogenic platform for coupling color centers in diamond membranes to a fiberbased microcavity

We operate a fiberbased cavity with an inserted diamond membrane containing ensembles of silicon vacancy centers (SiV$^-$) at cryogenic temperatures $ \geq4~$K. The setup, sample fabrication and spectroscopic characterization is described, together with a demonstration of the cavity influence by the Purcell effect. This paves the way towards solid state qubits coupled to optical interfaces as long-lived quantum memories.

quant-ph↗
arXiv2020

Embedded Readout Electronics R&D for the Large PMTs in the JUNO Experiment

Jiangmen Underground neutrino Observatory (JUNO) is a next generation liquid scintillator neutrino experiment under construction phase in South China. Thanks to the anti-neutrinos produced by the nearby nuclear power plants, JUNO will primarily study the neutrino mass hierarchy, one of the open key questions in neutrino physics. One key ingredient for the success of the measurement is to use high speed, high resolution sampling electronics located very close to the detector signal. Linearity in the response of the electronics in another important ingredient for the success of the experiment. During the initial design phase of the electronics, a custom design, with the Front-End and Read-Out electronics located very close to the detector analog signal has been developed and successfully tested. The present paper describes the electronics structure and the first tests performed on the prototypes. The electronics prototypes have been tested and they show good linearity response, with a maximum deviation of 1.3% over the full dynamic range (1-1000 p.e.), fulfilling the JUNO experiment requirements.

physics.ins-det↗
arXiv2019

Shuttling-Based Trapped-Ion Quantum Information Processing

Moving trapped-ion qubits in a microstructured array of radiofrequency traps offers a route towards realizing scalable quantum processing nodes. Establishing such nodes, providing sufficient functionality to represent a building block for emerging quantum technologies, e.g. a quantum computer or quantum repeater, remains a formidable technological challenge. In this review, we present a holistic view on such an architecture, including the relevant components, their characterization and their impact on the overall system performance. We present a hardware architecture based on a uniform linear segmented multilayer trap, controlled by a custom-made fast multi-channel arbitrary waveform generator. The latter allows for conducting a set of different ion shuttling operations at sufficient speed and quality. We describe the relevant parameters and performance specifications for microstructured ion traps, waveform generators and additional circuitry, along with suitable measurement schemes to verify the system performance. Furthermore, a set of different basic shuttling operations for dynamic qubit register reconfiguration is described and characterized in detail.

quant-ph↗
arXiv2019

Electrostatic deflector studies using small prototypes

The search for electric dipole moments of particles in storage rings requires the development of dedicated deflector elements with electrostatic fields. In these rings, electric deflectors shall be used as bending elements for the charged particles. This paper presents studies on scaled-down prototypes, a few cm in size, to investigate different deflector materials at similar electric fields but much smaller distances than real size prototypes.

physics.ins-det↗
arXiv2019

Feasibility Study for an EDM Storage Ring

This project exploits charged particles confined as a storage ring beam (proton, deuteron, possibly $^3$He) to search for an intrinsic electric dipole moment (EDM, $\vec d$) aligned along the particle spin axis. Statistical sensitivities can approach $10^{-29}$~e$\cdot$cm. The challenge will be to reduce systematic errors to similar levels. The ring will be adjusted to preserve the spin polarization, initially parallel to the particle velocity, for times in excess of 15 minutes. Large radial electric fields, acting through the EDM, will rotate the polarization ($\vec d \times\vec E$). The slow rise in the vertical polarization component, detected through scattering from a target, signals the EDM. The project strategy is outlined. It foresees a step-wise plan, starting with ongoing COSY activities that demonstrate technical feasibility. Achievements to date include reduced polarization measurement errors, long horizontal-plane polarization lifetimes, and control of the polarization direction through feedback from the scattering measurements. The project continues with a proof-of-capability measurement (precursor experiment; first direct deuteron EDM measurement), an intermediate prototype ring (proof-of-principle; demonstrator for key technologies), and finally the high precision electric-field storage ring.

physics.acc-ph↗