arXiv subjects

E. Garutti

Publications and source records attributed to E. Garutti.

At least 19 recordsLinked to original sources

arXiv2026

An investigation of fast simulation techniques for pion showers using kernel density estimators with the CALICE AHCAL Technological Prototype

In this article, the development and investigation of fast hadron shower simulation methods is presented. A test beam dataset has been recorded in 2018 at CERN with the AHCAL Technological Prototype of the CALICE Collaboration, where the calorimeter prototype was exposed to electron, muon, and negatively charged pion beams of various initial energies. The pion shower dataset, covering energies between 10 GeV and 200 GeV, has been used to develop a data-driven fast simulation algorithm of the AHCAL response to pion showers. The resulting shower model demonstrates excellent agreement with measured shower observables. In addition, a method for simulating pion showers at arbitrary energies is introduced, based upon interpolation between simulated showers at neighbouring beam energies.

physics.ins-det↗

arXiv2026

Characterization of afterpulse in SiPMs with single-cell readout as a function of bias voltage and fluence

We present a detailed investigation of the afterpulse effect in silicon photomultipliers (SiPMs), using a dedicated structure with single-cell readout. This enables direct measurement of intrinsic device properties and observation of individual pulses even after irradiation. Three independent analysis methods to quantify afterpulse induced events were developed and validated by Monte Carlo simulations. The first method is based on charge integration, while the other two methods use multiple linear regression to reconstruct transient waveforms and accurately identify individual pulse positions. These positions are then used either as direct event counts or to construct time interval distributions, enabling comprehensive characterization of the afterpulse probability and providing insights into the dynamics of trapping in silicon. Using this framework, we measured three SiPM samples: one fresh reference device and two irradiated devices exposed to reactor neutron fluences of 2e12 and 1e13 cm^-2. We report systematic measurements of the afterpulse probability and time constant as functions of bias voltage and irradiation fluence. For overvoltages in the range of 3 to 5 V above breakdown, the afterpulse time constant is found to be below 10 ns and the afterpulse probability below 6%. Both quantities show no significant dependence on irradiation fluence.

physics.ins-det↗

arXiv2026

Sensitivity of a closed dielectric haloscope to axion dark matter

We present a method to determine the sensitivity of a closed dielectric haloscope to axion dark matter. Dielectric haloscopes aim to probe the theoretically well-motivated axion mass range of ~26 $\mathrm{\mu}$eV to ~500 $\mathrm{\mu}$eV by utilizing a stack of dielectric disks and a mirror to enhance the axion-photon conversion within an external magnetic field. Their conversion volume is nearly axion-mass independent, thereby favoring large-scale designs to increase sensitivity. The large volume causes simulations to be computationally expensive and time-consuming. This paper presents a simple model that can be used to determine the sensitivity of the experiment with minimal computational resources. The model is able to describe the electromagnetic response of a closed dielectric haloscope, accounting for realistic geometric imperfections, as well as the noise introduced by the receiver system. It is applied to data taken with a MAgnetized Disk and Mirror Axion Experiment (MADMAX) prototype within the 1.6 T Morpurgo magnet at CERN. This work underpins the first axion dark matter search using a dielectric haloscope and provides the foundation for future dark matter searches with MADMAX.

astro-ph.IM↗

arXiv2025

A new Limit for Axion Dark Matter with SPACE

The axion, which has yet to be discovered, is a promising candidate for dark matter that emerges from Peccei-Quinn theory. This article presents the search for axion dark matter with the "Student Project for an Axion Cavity Experiment" (SPACE), which is also the first one in Germany. The hypothetical particle was looked for in the mass range from $16.626~\mathrm{\mu eV}$ to $16.653~\mathrm{\mu eV}$, corresponding to a frequency range of 4.020 GHz to 4.027 GHz, using a resonant cavity in a peak magnetic field of 14 T. No significant signal was found, allowing us to exclude an axion-photon coupling $g_{a\gamma\gamma} = 14.6 \cdot 10^{-13}~\mathrm{GeV}^{-1}$ for the full mass range and $g_{a\gamma\gamma} = 2.811 \cdot 10^{-13}~\mathrm{GeV}^{-1}$ at peak sensitivity with a 95% confidence level. This limit surpasses previous constraints by more than two orders of magnitude.

hep-ex↗

arXiv2025

The ILD Detector: A Versatile Detector for an Electron-Positron Collider at Energies up to 1 TeV

The International Large Detector, ILD, is a detector concept for an experiment at a future high energy lepton collider. The detector has been optimised for precision physics in a range of energies from 90~GeV to about 1~TeV. ILD features a high precision, large volume combined silicon and gaseous tracking system, together with a high granularity calorimeter, all inside a central solenoidal magnetic field. The paradigm of particle flow has been the guiding principle of the design of ILD. ILD is based mostly on technologies which have been demonstrated by extensive research and test programs. The ILD concept is proposed both for linear and circular lepton collider, be it at CERN or elsewhere. The concept has been developed by a group of nearly 60 institutes from around the world, and offers a well developed and powerful environment for science and technology studies at lepton colliders. In this document, the required performance of the detector, the proposed implementation and the readiness of the different technologies needed for the implementation are discussed.

hep-ex↗

arXiv2024

Is the gain-voltage dependence of SiPMs linear?

The gain-voltage dependence for SiPMs from V. Chmill et al., Study of the breakdown voltage of SiPMs, is reanalyzed and a non-linearity at the sub-percent level is observed. Simulations show that he non-linearity can be explained by the increase of the depletion depth of the avalanche region with over-voltage. A consequence of the non-linearity is that the voltage at which the discharge stops is systematically underestimated if a linear extrapolation is used. However, the shift is too small to explain the difference between the break-down voltage from the current-voltage dependence and the one obtained from the extrapolation of the gain-voltage dependence to gain one. The results are confirmed by measurement of a different MPPC produced by Hamamatsu which has a break-down voltage which is about a factor two higher.

cond-mat.mtrl-sci↗

arXiv2024

First search for axion dark matter with a Madmax prototype

This paper presents the first search for dark matter axions with mass in the ranges 76.56 to 76.82 $\mu$eV and 79.31 to 79.53 $\mu$eV using a prototype setup for the MAgnetized Disk and Mirror Axion eXperiment (MADMAX). The experimental setup employs a dielectric haloscope consisting of three sapphire disks and a mirror to resonantly enhance the axion-induced microwave signal within the magnetic dipole field provided by the 1.6 T Morpurgo magnet at CERN. Over 14.5 days of data collection, no axion signal was detected. A 95% CL upper limit on the axion-photon coupling strength down to $|g_{a\gamma}| \sim 2 \times 10^{-11} \mathrm{GeV}^{-1}$ is set in the targeted mass ranges, surpassing previous constraints, assuming a local axion dark matter density $\rho_{a}$ of $0.3~\mathrm{GeV}/\mathrm{cm}^3$. This study marks the first axion dark matter search using a dielectric haloscope.

hep-ex↗

arXiv2024

Precision determination of the track-position resolution of beam telescopes

Beam tests using tracking telescopes are a standard method for determining the spatial resolution of detectors. This requires the precise knowledge of the position resolution of beam tracks reconstructed at the Device Under Test (DUT). A method is proposed which achieves this using a segmented silicon detector with readout with charge digitization. It is found that the DUT spatial resolution for particles with normal incidence is less than 1 $\mu$m for events where clusters consist of two pixels (or strips). Given this accuracy, the residual of the beam track-position at the DUT and the position reconstructed in the DUT provides the beam track-position resolution distribution. The method is developed using simulated events, which are also used to study how to deal with cross-talk, electronics noise, energetic $\delta $-electrons, and incident beams with a few degrees off the normal to the sensor plane. To validate the method, the position resolution of beam tracks reconstructed by the EUDET beam telescope of the DESY II Test Beam Facility is determined using a CMS Phase-2 prototype pixel sensor.

physics.ins-det↗

arXiv2024

First search for dark photon dark matter with a MADMAX prototype

We report the first result from a dark photon dark matter search in the mass range from ${78.62}$ to $83.95~\mathrm{\mu eV}/c^2$ with a dielectric haloscope prototype for MADMAX (Magnetized Disc and Mirror Axion eXperiment). Putative dark photons would convert to observable photons within a stack consisting of three sapphire disks and a mirror. The emitted power of this system is received by an antenna and successively digitized using a low-noise receiver. No dark photon signal has been observed. Assuming unpolarized dark photon dark matter with a local density of $\rho_{\chi}=0.3~\mathrm{GeV/cm^3}$ we exclude a dark photon to photon mixing parameter $\chi > 2.7 \times 10^{-12}$ over the full mass range and $\chi > 1.1 \times 10^{-13}$ at a mass of $80.57~\mathrm{\mu eV}/c^2$ with a 95\% confidence level. This is the first physics result from a MADMAX prototype and exceeds previous constraints on $\chi$ in this mass range by up to almost three orders of magnitude.

hep-ex↗

arXiv2024

First mechanical realization of a tunable dielectric haloscope for the MADMAX axion search experiment

MADMAX, a future experiment to search for axion dark matter, is based on a novel detection concept called the dielectric haloscope. It consists of a booster composed of several dielectric disks positioned with $\mu$m precision. A prototype composed of one movable disk was built to demonstrate the mechanical feasibility of such a booster in the challenging environment of the experiment: high magnetic field to convert the axions into photons and cryogenic temperature to reduce the thermal noise. It was tested both inside a strong magnetic field up to 1.6 T and at cryogenic temperatures down to 35K. The measurements of the velocity and positioning accuracy of the disk are shown and are found to match the MADMAX requirements.

physics.ins-det↗

arXiv2024

Shower Separation in Five Dimensions for Highly Granular Calorimeters using Machine Learning

To achieve state-of-the-art jet energy resolution for Particle Flow, sophisticated energy clustering algorithms must be developed that can fully exploit available information to separate energy deposits from charged and neutral particles. Three published neural network-based shower separation models were applied to simulation and experimental data to measure the performance of the highly granular CALICE Analogue Hadronic Calorimeter (AHCAL) technological prototype in distinguishing the energy deposited by a single charged and single neutral hadron for Particle Flow. The performance of models trained using only standard spatial and energy and charged track position information from an event was compared to models trained using timing information available from AHCAL, which is expected to improve sensitivity to shower development and, therefore, aid in clustering. Both simulation and experimental data were used to train and test the models and their performances were compared. The best-performing neural network achieved significantly superior event reconstruction when timing information was utilised in training for the case where the charged hadron had more energy than the neutral one, motivating temporally sensitive calorimeters. All models under test were observed to tend to allocate energy deposited by the more energetic of the two showers to the less energetic one. Similar shower reconstruction performance was observed for a model trained on simulation and applied to data and a model trained and applied to data.

physics.ins-det↗

arXiv2024

Software Compensation for Highly Granular Calorimeters using Machine Learning

A neural network for software compensation was developed for the highly granular CALICE Analogue Hadronic Calorimeter (AHCAL). The neural network uses spatial and temporal event information from the AHCAL and energy information, which is expected to improve sensitivity to shower development and the neutron fraction of the hadron shower. The neural network method produced a depth-dependent energy weighting and a time-dependent threshold for enhancing energy deposits consistent with the timescale of evaporation neutrons. Additionally, it was observed to learn an energy-weighting indicative of longitudinal leakage correction. In addition, the method produced a linear detector response and outperformed a published control method regarding resolution for every particle energy studied.

physics.ins-det↗

arXiv2023

Experimental determination of axion signal power of dish antennas and dielectric haloscopes using the reciprocity approach

The reciprocity approach is a powerful method to determine the expected signal power of axion haloscopes in a model-independent way. Especially for open and broadband setups like the MADMAX dielectric haloscope the sensitivity to the axion field is difficult to calibrate since they do not allow discrete eigenmode analysis and are optically too large to fully simulate. The central idea of the reciprocity approach is to measure a reflection-induced test field in the setup instead of trying to simulate the axion-induced field. In this article, the reciprocity approach is used to determine the expected signal power of a dish antenna and a minimal dielectric haloscope directly from measurements. The results match expectations from simulation but also include important systematic effects that are too difficult to simulate. In particular, the effect of antenna standing waves and higher order mode perturbations can be quantified for the first time in a dielectric haloscope.

hep-ex↗

arXiv2023

Qualification of piezo-electric actuators for the MADMAX booster system at cryogenic temperatures and high magnetic fields

We report on the qualification of a piezo-based linear stage for the manipulation of positions of dielectric discs in the booster of the MADMAX axion dark matter search experiment. A first demonstrator of the piezo drives, specifically developed for MADMAX, was tested at room temperature as well as at cryogenic temperatures down to 4.5 K and inside strong magnetic fields up to 5.3 T. These qualification measurements prove that the piezo-based linear stage is suited for MADMAX and fulfills the requirements.

physics.ins-det↗

arXiv2022

Self-heating Effect in Silicon-Photomultipliers

The main effect of radiation damage in a Silicon-Photolumtiplier (SiPM) is a dramatic increase in the dark current. The power dissipated, if not properly cooled, heats the SiPM, whose performance parameters depend on temperature. Heating studies were performed with a KETEK SiPM, glued on an Al$_2$O$_3$ substrate, which is either directly connected to the temperature-controlled chuck of a probe station, or through layers of material with well-known thermal resistance. The SiPM is illuminated by a LED operated in DC-mode. The SiPM current is measured and used to determine the steady-state temperature as a function of power dissipated in the multiplication region of the SiPM and thermal resistance, as well as the time dependencies for heating and cooling. This information can be used to correct the parameters determined for radiation-damaged SiPM for the effects of self-heating. The method can also be employed for packaged SiPMs with unknown thermal contact to a heat sink. The results presented in this paper are preliminary.

physics.ins-det↗

arXiv2022

Radiation damage uniformity in a SiPM

A dedicated single-cell SiPM structure is designed and measured to investigate the radiation damage effects on the gain and breakdown voltage of SiPMs exposed to a reactor neutron fluence up to $Φ$ = 5e13 cm$^{-2}$. The cell has a pitch of 15 $μ$m. Results of the measurements and analysis of the IV-curves are presented. Impact of the self-heating effect was investigated. The radiation damage uniformity of 1 cell and 120 cells was checked up to $U_\mathit{ov}$ = 1.7 V. Fluence dependence of the breakdown voltage from the current measurements $U^{IV}_\mathit{bd}$ was extracted and compared to that of the breakdown voltage from the gain measurements $U^{G}_\mathit{bd}$.

physics.ins-det↗

arXiv2021

Radiation hardness study using SiPMs with single-cell readout

A dedicated single-cell SiPM structure is designed and measured to investigate the radiation damage effects on the gain and turn-off voltage of SiPMs exposed to a reactor neutron fluence up to $Φ$ = 5e13 cm$^{-2}$. The cell has a pitch of 15 $μ$m. The fluence dependence of gain and turn-off voltage are reported. A reduction of the gain by 19% and an increase of $V_{off}$ by $\approx$0.5 V is observed after $Φ$ = 5e13 cm$^{-2}$.

physics.ins-det↗

arXiv2021

Simulating MADMAX in 3D: Requirements for Dielectric Axion Haloscopes

We present 3D calculations for dielectric haloscopes such as the currently envisioned MADMAX experiment. For ideal systems with perfectly flat, parallel and isotropic dielectric disks of finite diameter, we find that a geometrical form factor reduces the emitted power by up to $30\,\%$ compared to earlier 1D calculations. We derive the emitted beam shape, which is important for antenna design. We show that realistic dark matter axion velocities of $10^{-3} c$ and inhomogeneities of the external magnetic field at the scale of $10\,\%$ have negligible impact on the sensitivity of MADMAX. We investigate design requirements for which the emitted power changes by less than $20\,\%$ for a benchmark boost factor with a bandwidth of $50\,{\rm MHz}$ at $22\,{\rm GHz}$, corresponding to an axion mass of $90\,μ{\rm eV}$. We find that the maximum allowed disk tilt is $100\,μ{\rm m}$ divided by the disk diameter, the required disk planarity is $20\,μ{\rm m}$ (min-to-max) or better, and the maximum allowed surface roughness is $100\,μ{\rm m}$ (min-to-max). We show how using tiled dielectric disks glued together from multiple smaller patches can affect the beam shape and antenna coupling.

hep-ex↗