arXiv subjects

Florian Jörg

Publications and source records attributed to Florian Jörg.

10 recordsLinked to original sources

arXiv2026

Mineral Detection of Neutrinos and Dark Matter 2026 Proceedings

The fourth "Mineral Detection of Neutrinos and Dark Matter" (MDvDM'26) meeting was held April 14-17, 2026 in Karlsruhe, Germany, hosted by the Institute for Astroparticle Physics (IAP) at Karlsruhe Institute of Technology (KIT). These proceedings detail the contributions that were presented during MDvDM'26, illustrating the unprecedented progress in theoretical, computational and experimental studies towards the realization of the concept of mineral detectors. Mineral detectors represent an emerging particle detection concept that has risen in prominence in recent years due to the advent of modern computational and high-resolution microscopy techniques. Natural and synthetic crystals are capable of retaining microscopic damage features induced by nuclear recoils, which could be then read out with a variety of micrometer and nanometer resolution microscopy techniques. On laboratory time scales mineral detectors could be employed for reactor neutrino monitoring and dark matter detection, with the potential to measure the directions as well as the energies of the induced nuclear recoils. Uniquely, ancient natural crystals (so-called paleo-detectors) that have been recording nuclear recoils over geological timescales could be used for studying astrophysical neutrinos, cosmic rays, dark matter and heavy exotic particles, as well as the variation of their fluxes over our Galaxy's lifetime. In recent years the international MDvDM community has been successfully tackling the challenges associated with realizing the concept of mineral detectors, opening the pathway towards a fully fledged experimental program and potential future discoveries.

physics.ins-det↗

arXiv2026

Application of surface coating for radon mitigation in rare-event searches

Rare-event searches offer a powerful avenue for investigating some of the most fundamental questions in modern physics, most prominently the particle nature of dark matter and the possible Majorana nature of the neutrino. Often, their dominant source of background comes from the radioactive noble gas radon emanating from materials. We report on a novel strategy to mitigate this background by the application of coating layers. A method for electroplating of copper was developed that showed a thousandfold reduction of the $^{222}$Rn emanation rate from a $^{226}$Ra-implanted stainless steel sample.

physics.ins-det↗

arXiv2025

Characterisation of the Bedretto Underground Site for Fundamental Physics Experiments

Underground laboratories provide the ultra-low background and low-vibration environments essential for rare-event searches, gravitational-wave detection, and quantum-sensing technologies. We report a comprehensive environmental characterisation of the Bedretto tunnel in Ticino, Switzerland, a site offering horizontal access, excellent infrastructure, and the potential to be be Europe's second-deepest and quietest underground laboratory. At the prospective physics site, located beneath an overburden exceeding 1400 m, we measure the cosmic-muon, gamma-ray, and neutron fluxes, as well as the radon concentration, magnetic-field spectrum, and seismic backgrounds. The muon flux is suppressed by six orders of magnitude relative to the surface, consistent with an effective depth of about 4000 metre water equivalent, gamma-ray and neutron measurements reflect the local geology and guide shielding requirements for future particle and nuclear physics experiments. Magnetic and seismic noise levels are found to be exceptionally low, meeting or exceeding the criteria for next-generation atom-interferometric gravitational-wave detectors. These results establish the site as a highly competitive, accessible deep-underground location for fundamental-physics experiments.

astro-ph.IM↗

arXiv2024

Investigating the slow component of the infrared scintillation time response in gaseous xenon

Xenon is the target material of choice in several rare event searches. The use of infrared (IR) scintillation light, in addition to the commonly used vacuum ultraviolet (VUV) light, could increase the sensitivity of these experiments. Understanding the IR scintillation response of xenon is essential in assessing the potential for improvement. This study focuses on characterizing the time response and light yield (LY) of IR scintillation in gaseous xenon for alpha particles at atmospheric pressure and room temperature. We have previously observed that the time response can be described by two components: one with a fast time constant of O(ns) and one with a slow time constant of O($\mathrmμ$s). This work presents new measurements that improve our understanding of the slow component. The experimental setup was modified to allow for a measurement of the IR scintillation time response with a ten times longer time window of about 3 $\mathrmμ$s, effectively mitigating the dominant systematic uncertainty of the LY measurement. We find that the slow component at about 1 bar pressure can be described by a single exponential function with a decay time of about 850 ns. The LY is found to be (6347 $\pm$ 22 (stat) $\pm$ 400 (syst)) ph / MeV, consistent with our previous measurement. In addition, a measurement with zero electric field along the alpha particle tracks was conducted to rule out the possibility that the slow component is dominated by light emission from drifting electrons or the recombination of electrons and ions.

physics.ins-det↗

arXiv2023

Characterization of a $^{220}$Rn source for low-energy electronic recoil calibration of the XENONnT detector

Low-background liquid xenon detectors are utilized in the investigation of rare events, including dark matter and neutrinoless double beta decay. For their calibration, gaseous $^{220}$Rn can be used. After being introduced into the xenon, its progeny isotope $^{212}$Pb induces homogeneously distributed, low-energy ($<30$ keV) electronic recoil interactions. We report on the characterization of such a source for use in the XENONnT experiment. It consists of four commercially available $^{228}$Th sources with an activity of 55 kBq. These sources provide a high $^{220}$Rn emanation rate of about 8 kBq. We find no indication for the release of the long-lived $^{228}$Th above 1.7 mBq. Though an unexpected $^{222}$Rn emanation rate of about 3.6 mBq is observed, this source is still in line with the requirements for the XENONnT experiment.

physics.ins-det↗

arXiv2023

First time-resolved measurement of infrared scintillation light in gaseous xenon

Xenon is a widely used detector target material due to its excellent scintillation properties in the ultraviolet (UV) spectrum. The additional use of infrared (IR) scintillation light could improve future detectors. However, a comprehensive characterization of the IR component is necessary to explore its potential. We report on the first measurement of the time profile of the IR scintillation response of gaseous xenon. Our setup consists of a gaseous xenon target irradiated by an alpha particle source and is instrumented with one IR- and two UV-sensitive photomultiplier tubes. Thereby, it enables IR timing measurements with nanosecond resolution and simultaneous measurement of UV and IR signals. We find that the IR light yield is in the same order of magnitude as the UV yield. We observe that the IR pulses can be described by a fast and a slow component and demonstrate that the size of the slow component decreases with increasing levels of impurities in the gas. Moreover, we study the IR emission as a function of pressure. These findings confirm earlier observations and advance our understanding of the IR scintillation response of gaseous xenon, which could have implications for the development of novel xenon-based detectors.

physics.ins-det↗

arXiv2023

Production and characterization of a $^{222}$Rn-emanating stainless steel source

Precise radon measurements are a requirement for various applications, ranging from radiation protection over environmental studies to material screening campaigns for rare-event searches. All of them ultimately depend on the availability of calibration sources with a known and stable radon emanation rate. A new approach to produce clean and dry radon sources by implantation of $^{226}$Ra ions into stainless steel has been investigated. In a proof of principle study, two stainless steel plates have been implanted in collaboration with the ISOLDE facility located at CERN. We present results from a complete characterization of the sources. Each sample provides a radon emanation rate of about 2 Bq, which has been measured using electrostatic radon monitors as well as miniaturized proportional counters. Additional measurements using HPGe and alpha spectrometry as well as measurements of the radon emanation rate at low temperatures were carried out.

physics.ins-det↗

arXiv2022

Scintillation decay-time constants for alpha particles and electrons in liquid xenon

Understanding liquid xenon scintillation and ionization processes is of great interest to improve analysis methods in current and future detectors. In this paper, we investigate the dynamics of the scintillation process for excitation by $\mathcal{O}$(10 keV) electrons from a $^{83m}$Kr source and $\mathcal{O}$(6 MeV) $α$-particles from a $^{222}$Rn source, both mixed with the xenon target. The single photon sampling method is used to record photon arrival times in order to obtain the corresponding time distributions for different applied electric fields between about 0.8 V/cm to 1.2 kV/cm. Energy and field dependences of the signals which are observed in the results are discussed.

physics.ins-det↗

arXiv2022

Characterization of alpha and beta interactions in liquid xenon

Liquid xenon based detectors have achieved great sensitivities in rare event searches. Precise knowledge of the scintillation and ionization responses of the medium is essential to correctly model different interaction types in the detector including both signal and background-like ones. The response of liquid xenon to low energy electrons and to alpha particles has been studied in the Heidelberg Xenon (HeXe) dual-phase xenon TPC. We determine the light and charge signal yields for keV-energy electrons and MeV-energy alpha particles as well as the electron drift velocity for electric drift fields between 7.5 and 1640 V/cm. A three dimensional simulation using COMSOL Multiphysics(R) is used to characterize the applied drift field and its homogeneity.

physics.ins-det↗

arXiv2020

Transmission of xenon scintillation light through PTFE

Polytetrafluoroethylene (PTFE), also known as Teflon, is a common material used in the construction of liquid xenon detectors due to its high reflectivity for the VUV scintillation light of xenon. We present transmission measurements of PTFE for xenon scintillation light with peak emission at a wavelength of 175 nm. PTFE discs of different thicknesses are installed in front of a photosensor in two setups. One is filled with gaseous xenon, the other with liquid xenon. The measurements performed with the gaseous xenon setup at room temperature yield a transmission coefficient of $λ= \bigl(350{{}^{+60}_{~-0}}{}\,{\mathrm{(sys)}}\,\pm\, 50\,{\mathrm{(stat)}}\bigr)\,\mathrm{μm}$. This is found to be in agreement with the observations made using the liquid xenon setup.

physics.ins-det↗