Journal of Instrumentation

The Compact Muon Solenoid (CMS) detector is described. The detector operates at the Large Hadron Collider (LHC) at CERN. It was conceived to study proton-proton (and lead-lead) collisions at a centre-of-mass energy of 14 TeV (5.5 TeV nucleon-nucleon) and at luminosities up to 10³⁴ cm⁻² s⁻¹ (10²⁷ cm⁻² s⁻¹). At the core of the CMS detector sits a high-magnetic-field and large-bore superconducting solenoid surrounding an all-silicon pixel and strip tracker, a lead-tungstate scintillating-crystals electromagnetic calorimeter, and a brass-scintillator sampling hadron calorimeter. The iron yoke of the flux-return is instrumented with four stations of muon detectors covering most of the 4π solid angle. Forward sampling calorimeters extend the pseudorapidity coverage to high values (|η| ⩽ 5) assuring very good hermeticity. The overall dimensions of the CMS detector are a length of 21.6 m, a diameter of 14.6 m and a total weight of 12500 t.

The ATLAS detector as installed in its experimental cavern at point 1 at CERN is described in this paper. A brief overview of the expected performance of the detector when the Large Hadron Collider begins operation is also presented.

The ATLAS detector is installed in its experimental cavern at Point 1 of the CERN Large Hadron Collider. During Run 2 of the LHC, a luminosity of   = 2 × 10³⁴ cm^-2 s^-1 was routinely achieved at the start of fills, twice the design luminosity. For Run 3, accelerator improvements, notably luminosity levelling, allow sustained running at an instantaneous luminosity of   = 2 × 10³⁴ cm^-2 s^-1, with an average of up to 60 interactions per bunch crossing. The ATLAS detector has been upgraded to recover Run 1 single-lepton trigger thresholds while operating comfortably under Run 3 sustained pileup conditions. A fourth pixel layer 3.3 cm from the beam axis was added before Run 2 to improve vertex reconstruction and b-tagging performance. New Liquid Argon Calorimeter digital trigger electronics, with corresponding upgrades to the Trigger and Data Acquisition system, take advantage of a factor of 10 finer granularity to improve triggering on electrons, photons, taus, and hadronic signatures through increased pileup rejection. The inner muon endcap wheels were replaced by New Small Wheels with Micromegas and small-strip Thin Gap Chamber detectors, providing both precision tracking and Level-1 Muon trigger functionality. Trigger coverage of the inner barrel muon layer near one endcap region was augmented with modules integrating new thin-gap resistive plate chambers and smaller-diameter drift-tube chambers. Tile Calorimeter scintillation counters were added to improve electron energy resolution and background rejection. Upgrades to Minimum Bias Trigger Scintillators and Forward Detectors improve luminosity monitoring and enable total proton-proton cross section, diffractive physics, and heavy ion measurements. These upgrades are all compatible with operation in the much harsher environment anticipated after the High-Luminosity upgrade of the LHC and are the first steps towards preparing ATLAS for the High-Luminosity upgrade of the LHC. This paper describes the Run 3 configuration of the ATLAS detector.

The Large Hadron Collider (LHC) at CERN near Geneva is the world's newest and most powerful tool for Particle Physics research. It is designed to collide proton beams with a centre-of-mass energy of 14 TeV and an unprecedented luminosity of 10³⁴ cm⁻² s⁻¹. It can also collide heavy (Pb) ions with an energy of 2.8 TeV per nucleon and a peak luminosity of 10²⁷ cm⁻² s⁻¹. In this paper, the machine design is described.

The LHCb experiment is dedicated to precision measurements of CP violation and rare decays of B hadrons at the Large Hadron Collider (LHC) at CERN (Geneva). The initial configuration and expected performance of the detector and associated systems, as established by test beam measurements and simulation studies, is described.

The international collaboration designing and constructing the Deep Underground Neutrino Experiment (DUNE) at the Long-Baseline Neutrino Facility (LBNF) has developed a two-phase strategy toward the implementation of this leading-edge, large-scale science project. The 2023 report of the US Particle Physics Project Prioritization Panel (P5) reaffirmed this vision and strongly endorsed DUNE Phase I and Phase II, as did the European Strategy for Particle Physics. While the construction of the DUNE Phase I is well underway, this White Paper focuses on DUNE Phase II planning. DUNE Phase-II consists of a third and fourth far detector (FD) module, an upgraded near detector complex, and an enhanced 2.1 MW beam. The fourth FD module is conceived as a "Module of Opportunity", aimed at expanding the physics opportunities, in addition to supporting the core DUNE science program, with more advanced technologies. This document highlights the increased science opportunities offered by the DUNE Phase II near and far detectors, including long-baseline neutrino oscillation physics, neutrino astrophysics, and physics beyond the standard model. It describes the DUNE Phase II near and far detector technologies and detector design concepts that are currently under consideration. A summary of key R&D goals and prototyping phases needed to realize the Phase II detector technical designs is also provided. DUNE's Phase II detectors, along with the increased beam power, will complete the full scope of DUNE, enabling a multi-decadal program of groundbreaking science with neutrinos.

The high-luminosity phase of LHC operations (HL-LHC), will feature a large increase in simultaneous proton-proton interactions per bunch crossing up to 200, compared with a typical leveling target of 64 in Run 3. Such an increase will create a very challenging environment in which to perform charged particle trajectory reconstruction, a task crucial for the success of the ATLAS physics program, and will exceed the capabilities of the current ATLAS Inner Detector (ID). A new all-silicon Inner Tracker (ITk) will replace the current ID in time for the start of the HL-LHC. To ensure successful use of the ITk capabilities in Run 4 and beyond, the ATLAS tracking software has been successfully adapted to achieve state-of-the-art track reconstruction in challenging high-luminosity conditions with the ITk detector. This paper presents the expected tracking performance of the ATLAS ITk based on the latest available developments since the ITk technical design reports.

In this technical design report (TDR) executive summary we describe the SABRE South detector to be built at the Stawell Underground Physics Laboratory (SUPL). The SABRE South detector is designed to test the long-standing DAMA/LIBRA signal of an annually modulating rate consistent with dark matter by using the same target material. Located in the Southern Hemisphere, the detector is uniquely positioned to disentangle modulating seasonal effects. SABRE South uses seven ultra-high purity NaI(Tl) crystals (with a total target mass of either 35 kg or 50 kg), hermetically sealed in copper enclosures that are suspended within a liquid scintillator active veto. High quantum efficiency and low background Hamamatsu R11065 photomultiplier tubes are directly coupled to both ends of the crystal, and enclosed with the crystal in an oxygen free copper enclosure. The active veto system consists of 11.6 kL of linear alkylbenzene (LAB) doped with a mixture of fluorophores and contained in a steel vessel, which is instrumented with at least 18 Hamamatsu R5912 photomultipliers. The active veto tags key radiogenic backgrounds intrinsic to the crystals, such as  ⁴⁰K, and is expected to suppress the total background by 27% in the 1–6 keV region of interest. In addition to the liquid scintillator veto, a muon veto is positioned above the detector shielding. This muon veto consists of eight EJ-200 scintillator modules, with Hamamatsu R13089 photomultipliers coupled to both ends. With an expected total background of 0.72 cpd/kg/keV, SABRE South can test the DAMA/LIBRA signal with 5σ discovery or 3σ exclusion after two years of data taking.

A network of spectroscopic cameras was installed and successfully operated during the entire operation phase 1 of the optimized stellarator, Wendelstein 7-X. This diagnostic system enabled spatially resolved measurements of photon fluxes at specific wavelengths. Narrow band pass filters in the optical path allowed for targeted photon flux measurements of various spectral lines, specifically for the main ion species, hydrogen, and the primary impurity, carbon.

The cameras were arranged in a stellarator-symmetric configuration, with one camera assembly per half-module. Each camera was equipped with a 135 ° ultra-wide field-of-view lens centered on the divertor, enabling comprehensive observation of the entire divertor unit, including the baffle and most of the surrounding heat shield. This configuration achieved coverage of 56 % of all plasma-facing surfaces at W7-X, providing a spatial resolution up to 1.4 pixel/cm at a frame rate of 25 Hz.

This diagnostic system supports a wide range of applications, from studies of ionizing particle fluxes and wall recycling to investigations of plasma radiation and detachment, edge impurity sources, and their distribution. This paper details the diagnostic system's observation geometry, measurement principles, calibration processes, inter-diagnostic comparisons, synthetic diagnostic modeling, and plans for further development.

The preponderance of matter over antimatter in the early universe, the dynamics of the supernovae that produced the heavy elements necessary for life, and whether protons eventually decay—these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our universe, its current state, and its eventual fate. The Deep Underground Neutrino Experiment (DUNE) is an international world-class experiment dedicated to addressing these questions as it searches for leptonic charge-parity symmetry violation, stands ready to capture supernova neutrino bursts, and seeks to observe nucleon decay as a signature of a grand unified theory underlying the standard model. The DUNE far detector technical design report (TDR) describes the DUNE physics program and the technical designs of the single- and dual-phase DUNE liquid argon TPC far detector modules. This TDR is intended to justify the technical choices for the far detector that flow down from the high-level physics goals through requirements at all levels of the Project. Volume I contains an executive summary that introduces the DUNE science program, the far detector and the strategy for its modular designs, and the organization and management of the Project. The remainder of Volume I provides more detail on the science program that drives the choice of detector technologies and on the technologies themselves. It also introduces the designs for the DUNE near detector and the DUNE computing model, for which DUNE is planning design reports. Volume II of this TDR describes DUNE's physics program in detail. Volume III describes the technical coordination required for the far detector design, construction, installation, and integration, and its organizational structure. Volume IV describes the single-phase far detector technology. A planned Volume V will describe the dual-phase technology.

The Deep Underground Neutrino Experiment (DUNE) is a long-baseline (1300 km) neutrino experiment hosted at the Fermi National Accelerator Laboratory (FNAL). It aims to measure neutrino mass ordering and CP violation through neutrino oscillations from a characterized muon neutrino beam. DUNE will deploy four Liquid-Argon Time-Projection-Chamber (LArTPC) detectors with a total mass of approximately 70 kt. The reconstruction of particle interactions, both from the beam and external neutrino sources is achieved by collecting two distinct interaction signals: ionization electrons with the Time Projection Chamber (TPC) and scintillation photons (127 nm) with the Photon Detection System (PDS). Regarding the latter, to fulfil the physics requirements of the experiment, a uniform and efficient collection of the argon scintillation light across the 62 m × 15 m × 14 m detector volume is required to achieve an average detected light yield of at least 20 PE MeV^-1. For the case of DUNE's far detector module with vertical drift direction (FD-VD), the system relies on 672 X-ARAPUCA (XA) tiles, which trap photons inside their highly reflective box by shifting VUV light to visible wavelengths. An intensive R&D campaign, involving multiple international institutions, has optimized the design and component selection for the next-generation PDS modules, which have been tested in liquid argon using a dedicated cryogenic setup developed at CIEMAT to evaluate their photon detection efficiency (PDE). Several configurations have been chosen to evaluate the possible design improvements in terms of different light-trapping strategies and reflectiveness.

Electron Beam Ion Traps (EBITs) provide a controlled environment for studying electron-ion interactions, particularly in highly charged ions (HCIs), and enable precise measurement of processes, such as dielectronic recombination (DR). Using the compact Dresden EBIT at Jagiellonian University, we present new experimental data on DR in neon ions, collected for electron energy scanned in range of 700 to 1000 eV. The data were obtained with a silicon-drift X-ray detector (Bruker XFlash 5030), and results indicate resonant structures corresponding to DR, with the observed resonant-like K_β emission primarily attributed to He-like neon ions. However, low statistical precision highlights the challenges of achieving optimal signal quality in this setup, particularly due to low detection efficiency in the K-shell neon energy range. Planned improvements, including repositioning the detector closer to the trap and removing the beryllium window, are expected to enhance resolution and data acquisition efficiency in future studies.

An airborne survey system named the MARK-A1 was previously developed to be mounted on an unmanned aerial vehicle for the purpose of application in contaminated areas with high dose rate levels. The MARK-A1 system consists of a CZT detector, signal processing unit, and positioning and interface units linked to a PC on the ground. The weight of the system is below 1 kg for loading on a commercial drone. In the current work, for experimental verification, field testing was conducted in a high dose rate environment near the Fukushima Daiichi Nuclear Power Plant. With the cooperation of the Japan Atomic Energy Agency, the MARK-A1 was installed on an unmanned aerial vehicle to conduct airborne surveys using two flight methods, namely a flat flight and a step flight, at various speeds. The airborne survey data were converted to gamma dose rates at a height of 1 m above the ground using a flat source model to create contamination maps. For a comparative evaluation of the airborne survey results, an in situ survey was also conducted in the survey area, and it was confirmed that the step flight method better matched the surface survey results.

The Hefei Advanced Light Facility (HALF) electron storage ring employs longitudinal gradient bending magnets (LGBs) as its primary bending components. The storage ring's lattice comprises 20 cells, each containing six longitudinal gradient dipole magnets. To accommodate future energy upgrades, these magnets feature an electromagnet design that allows for a wide range of their magnetic fields. To meet the physical design requirements of a diffraction-limited storage ring, the integral field uniformity within the good field region (GFR) must be better than 0.05%, with orbit deviations constrained to less than 0.1 mm. This paper discusses the physical design, prototype construction, and magnetic field measurement results of the longitudinal gradient dipole magnets for HALF.

The Engineering Materials Diffractometer (EMD) at the China Spallation Neutron Source (CSNS) has been successfully commissioned as a state-of-the-art instrument for engineering materials characterization. Precise alignment of the neutron beamline, sample stage, and radial collimators, validated using a high-precision laser tracker and neutron beam experiments, ensures accurate measurements and forms the basis for the EMD's exceptional performance. This alignment enables the EMD to achieve a maximum neutron flux of 9.0 × 10⁶ n/s/cm² and a best resolution of 0.25% across a d-spacing range of 0.5 ∼ 2.6 Å at 140 kW. And the EMD demonstrated a strain resolution of 50 ∼ 100 microstrains, validated through in-situ tensile testing and VAMAS TWA 20 measurements, confirming its accuracy in characterizing elastic and residual strains. Its optimized operating modes-High-FOM, High-Resolution, and High-Intensity- support diverse applications such as residual stress analysis, in-situ experiments, and texture studies. The EMD's capabilities in precise residual stress measurement and in-situ tensile experiment make it a valuable tool for both academic and industrial research. This study not only highlights the EMD's successful commissioning but also provides a framework for future neutron optical system optimization, underscoring its potential to advance materials science in China and beyond.

Particle identification (PID) is one of the main strengths of the ALICE experiment at the LHC. It is a crucial ingredient for detailed studies of the strongly interacting matter formed in ultrarelativistic heavy-ion collisions. ALICE provides PID information via various experimental techniques, allowing for the identification of particles over a broad momentum range (from around 100 MeV/c to around 50 GeV/c). The main challenge is how to combine the information from various detectors effectively. Therefore, PID represents a model classification problem, which can be addressed using Machine Learning (ML) solutions. Moreover, the complexity of the detector and richness of the detection techniques make PID an interesting area of research also for the computer science community. In this work, we show the current status of the ML approach to PID in ALICE. We discuss the preliminary work with the Random Forest approach for the LHC Run 2 and a more advanced solution based on Domain Adaptation Neural Networks, including a proposal for its future implementation within the ALICE computing software for the upcoming LHC Run 3.

A fast wave interferometer (FWI), which can measure ion mass density, has been developed on DIII-D for its use on future fusion reactors, as well as for the study of ion behavior in current plasma devices. The frequency of the fast waves used for the FWI is around 60 MHz, and require antennas and coaxial cables or waveguides, which, unlike traditional mirror-based optical interferometers, are less susceptible to neutron/gamma-ray radiation and are relatively immune to impurity deposition and erosion as well as alignment issues. The bulk ion density evaluated using FWI show good agreement with that derived from CO₂ interferometry within about 15%. When the ion mass density measurement by FWI is combined with an electron density measurement from CO₂ interferometry, Z_eff measurements are also enabled and are in agreement with those from visible Bremsstrahlung measurements. Additionally, large-bandwidth FWI measurements clearly resolve 10–100 kHz coherent modes and demonstrate its potential as a core fluctuation diagnostic, sensitive to both magnetic and ion density perturbations.

KM3NeT (Cubic Kilometer Neutrino Telescope) is a research infrastructure that comprises two underwater neutrino detectors located at different sites in the Mediterranean Sea: KM3NeT-Fr (ORCA) (offshore the coast of Toulon, France, at a depth of around 2500 m) and KM3NeT-It (ARCA) (off Capo Passero, Sicily, Italy, at a depth of around 3500 m). The experiment consists of vertical structures, called strings, along which the optical modules are positioned. A hydrophone, located on the base of each string, is used for the reconstruction of the position of the KM3NeT elements with an accuracy of 10 cm. The presence of acoustic sensors in an underwater environment gives the opportunity to detect and study the sound emissions of marine mammals present in the area. The presented work describes the identification programs of the signals emitted by dolphins (clicks and whistles) and sperm whales (clicks) and the results of the analysis of real data collected between spring 2020 and spring 2021.

The Tracking Ultraviolet Set-up (TUS) is the world's first orbital imaging detector of Ultra High Energy Cosmic Rays (UHECR) and it operated in 2016–2017 as part of the scientific equipment of the Lomonosov satellite. The TUS was developed and manufactured as a prototype of the larger project K-EUSO with the main purpose of testing the efficiency of the method for measuring the ultraviolet signal of extensive air shower (EAS) in the Earth's night atmosphere. Despite the low spatial resolution (∼5 × 5  km² at sea level), several events were recorded which are very similar to EAS as for the signal profile and kinematics. Reconstruction of the parameters of such events is complicated by a short track length, an asymmetry of the image, and an uncertainty in the sensitivity distribution of the TUS channels. An advanced method was developed for the determination of event kinematic parameters including its arrival direction. In the present article, this method is applied for the analysis of 6 EAS-like events recorded by the TUS detector. All events have an out of space arrival direction with zenith angles less than 40°. Remarkably they were found to be over the land rather close to United States airports, which indicates a possible anthropogenic nature of the phenomenon. Detailed analysis revealed a correlation of the reconstructed tracks with direction to airport runways and Very High Frequency (VHF) omnidirectional range stations. The method developed here for reliable reconstruction of kinematic parameters of the track-like events, registered in low spatial resolution, will be useful in future space missions, such as K-EUSO.

We review the current status of liquid noble gas radiation detectors with energy threshold in the keV range, which are of interest for direct dark matter searches, measurement of coherent neutrino scattering and other low energy particle physics experiments. Emphasis is given to the operation principles and the most important instrumentation aspects of these detectors, principally of those operated in the double-phase mode. Recent technological advances and relevant developments in photon detection and charge readout are discussed in the context of their applicability to those experiments.

Electron Beam Ion Traps (EBITs) provide a controlled environment for studying electron-ion interactions, particularly in highly charged ions (HCIs), and enable precise measurement of processes, such as dielectronic recombination (DR). Using the compact Dresden EBIT at Jagiellonian University, we present new experimental data on DR in neon ions, collected for electron energy scanned in range of 700 to 1000 eV. The data were obtained with a silicon-drift X-ray detector (Bruker XFlash 5030), and results indicate resonant structures corresponding to DR, with the observed resonant-like K_β emission primarily attributed to He-like neon ions. However, low statistical precision highlights the challenges of achieving optimal signal quality in this setup, particularly due to low detection efficiency in the K-shell neon energy range. Planned improvements, including repositioning the detector closer to the trap and removing the beryllium window, are expected to enhance resolution and data acquisition efficiency in future studies.

The photon collection efficiency of gaseous scintillator detectors varies according to the position of the impinging charged particles in the medium that generates scintillation light. Thus, when impinging particles are distributed over a large area, the intrinsic photon-number resolution of the system is affected by a large variation. This work presents and discusses a method for adjusting the total number of detected photons to account for variation in the photon collection efficiency as a function of the position of the light source within the scintillating medium. The method was developed and validated by processing data from systematic simulation studies based on GEANT4 that model the response of the Energy Loss Optical Scintillation System (ELOSS) detector. The position of the charged particle is calculated using a deep neural network algorithm. This is accomplished by analyzing the distribution of scintillation light recorded by the array of photosensors. The estimated particle position is then used to calculate the correction factor and adjust the amount of captured light to account for variations in the photon collection efficiency. The neural network algorithm provides excellent tracking capabilities, achieving sub-millimeter position resolution and an angular resolution of 12 mrad, approaching the performance of traditional tracking detectors (e.g., drift chambers). The present method can be generalized to any optical scintillation system where the photon collection efficiency depends on the position of the impinging particle.

This study proposes a novel liquid scintillator-tungsten slice liquid medium electromagnetic calorimeter (ECAL). The design is based on the Shashlik structure, employing an ultra-thin liquid scintillator and tungsten slice alternate stacking strategy, aiming to achieve an excellent energy performance within limited space constraints for the future collider. Through Geant4 simulations, we have verified that the design has an energy resolution better than 5%@1GeV with a photoelectron yield of 100 p.e./mip, significantly superior to existing sampling calorimeter schemes. We fabricate a simple ECAL cell model and conducted cosmic ray tests, which achieve 170 p.e./mip and a 1% photonelectron collection and conversion efficiency. The mip signals compared between experimental and simulated demonstrated excellent consistency. Furthermore, the use of fast-emitting liquid scintillator as the sensitive material is expected to provide good timing performance, giving it the potential of a 5D calorimeter. This study not only provides a potential solution for future large collider experiments but also offers new ideas for the development of new calorimeters in other high-energy physics experiments.

Given the success of high-altitude wide-field gamma-ray detectors, such as HAWC and LHAASO, we explore a new gamma-hadron separation variable for the future Southern Wide-field Gamma-ray Observatory (SWGO), currently in the R&D phase. SWGO will be a ground-based, high duty cycle, extensive air shower water Cherenkov detector array with a high fill factor core, expected to be located in the Atacama Astronomical Park, Chile, at an altitude of 4770 m. To identify gamma ray astrophysical sources, primary particles need to be reconstructed from the air showers reaching the detector array using their characteristics to distinguish between gamma rays, considered as signal, and hadrons (i.e. cosmic rays) that are considered background. We use CORSIKA to simulate the development of air showers in the atmosphere up to the arrival of secondary particles at the array of water Cherenkov tanks. We propose the arrival time distribution of secondary particles reaching the detector array as an alternative gamma/hadron separator variable. To evaluate its performance we simulated photons and protons, as primary particles, in the energy range from 1 to 100 TeV for vertical events (i.e. zenith angle = 0°) reaching the center of the array. The optimal separation parameter found, given the above constraints, is the time of the 15% percentile of arriving particles inside a ring of 100 to 150 m. The recognized signal is ≳ 88% on average and the background rejection is ≳ 79%. Nevertheless, the overall time resolution of the tanks, estimated at 3.2 ns, is comparable to the average time separation between photons and protons, which is above 3.7 ns. Consequently, the actual efficiency of this variable is expected to be lower.

"Soft" muons with a transverse momentum below 10 GeV are featured in many processes studied by the CMS experiment, such as decays of heavy-flavor hadrons or rare tau lepton decays. Maximizing the selection efficiency for these muons, while simultaneously suppressing backgrounds from long-lived light-flavor hadron decays, is therefore important for the success of the CMS physics program. Multivariate techniques have been shown to deliver better muon identification performance than traditional selection techniques. To take full advantage of the large data set currently being collected during Run 3 of the CERN LHC, a new multivariate classifier based on a gradient-boosted decision tree has been developed. It offers a significantly improved separation of signal and background muons compared to a similar classifier used for the analysis of the Run 2 data. The performance of the new classifier is evaluated on a data set collected with the CMS detector in 2022 and 2023, corresponding to an integrated luminosity of 62 fb^-1.

Charge-exchange recombination with neutral atoms significantly influences the ionization balance in electron beam ion traps (EBIT) because its cross section is relatively large compared to cross sections of electron collision induced processes. Modeling the highly charged ion cloud requires the estimate of operating parameters, such as electron beam energy and density, the density of neutral atoms, and the relative velocities of collision partners. Uncertainty in the charge-exchange cross section can dominate the overall uncertainty in EBIT experiments, especially when it compounds with the uncertainties of experimental parameters that are difficult to determine. We present measured and simulated spectra of few-electron Fe ions, where we used a single charge-exchange factor to reduce the number of free parameters in the model. The deduction of the charge-exchange factor from the ratio of Li-like and He-like features allows for predicting the intensity of H-like lines in the spectra.

The muon anomalous magnetic moment, a_μ = g-2/2, is a low-energy observable which can be both measured and computed to high precision, making it a sensitive test of the Standard Model and a probe for new physics. This anomaly was measured with a precision of 0.20 parts per million (ppm) by the Fermilab's Muon g-2 (E989) experiment. The final goal of the E989 experiment is to reach a precision of 0.14 ppm. The experiment is based on the measurement of the muon spin anomalous precession frequency, ω_a, based on the arrival time distribution of high-energy decay positrons observed by 24 electromagnetic calorimeters, placed around the inner circumference of a 14 m diameter storage ring, and on the precise knowledge of the storage ring magnetic field and of the beam time and space distribution. Achieving this level of precision requires strict control over systematics, which is ensured through several diagnostic devices. At the accelerator level, these devices monitor the quality of the injected beam (e.g., verifying that it has the correct momentum), while at the detector level, they track both the magnetic field and the gain of the calorimeters. In this work the devices and techniques used by the E989 experiment will be presented.

Future neutrino experiments at low energies such as JUNO or Theia will use large volume homogeneous liquid scintillator detectors. The optical attenuation length of the liquid is of uttermost importance for the successful realization of these experiments. At TU Munich a new optical spectrometer (Precision Attenuation Length Measurement (PALM)) has been set up in order to measure the light attenuation of liquids which can be used for these types of experiments up to around 100 m in the wavelength region between 400 nm and 1000 nm. The setup features an optical imaging system with a long focal length, which allows for in-situ monitoring of the beam stability during the measurement. The setup capability as well as the reproducibility of its results has been demonstrated at two different wavelengths of 430 nm and 500 nm.

The uniformity calibration of a multilayer ionization chamber (MLIC) is crucial for ensuring the quality of depth dose distribution measurement and a comparative evaluation in the performance of calibration methods is lacking. In this study, we developed an MLIC and the mean water-equivalent length (WEL) of each layer was determined. The calibration coefficients of this MLIC were obtained through three different calibration methods and were used to correct the raw data of five energies. Measurements demonstrated high repeatability (average relative standard deviation ≤ 1.0% across all channels) for two key characteristic parameters of integrated depth dose (IDD): R₈₀, defined as the depth at which the dose falls off to 80% of its maximum value, and dose distal fall-off (DDF), defined as the distance between the distal 80% and 20% of the maximum dose. The short-term stability of these parameters was within ± 0.01 mm for R₈₀ and ± 0.001 mm for DDF, respectively. These three calibration methods showed insignificant contributions in reducing differences between R₈₀ and DDF values measured by the MLIC and their reference values in water. Across all five energies examined, the average relative deviations achieved with a so-called "shifted board" method, water phantom method and penetration method are 9.78%, 16.72%, and 15.55%, respectively. The shifted board method demonstrates superior agreement with reference profiles measured in a water phantom, surpassing the other two calibration methods.

Ion irradiation is established as a strong tool for tailored modifications of solid materials on the nanometer scale. Although experimental results show that these modifications depend on the ion's kinetic and potential energy deposition at the irradiated surface and within the material, the dynamics of the deposition processes are still unknown. Especially for semiconducting targets, models addressing the dynamics of ion-solid-interaction differ from each other, even though they lead to similar final states of ion irradiated targets. We present time-of-flight secondary neutral mass spectrometry studies on the influence of the potential and kinetic energy on the W sputter yield of a semiconducting WS₂ bulk crystal. In our studies we used highly charged Xe ions with potential energies between 12 keV and 39 keV and kinetic energies spanning from 20 keV to 260 keV. Our experiments show a linear dependence of the sputter yield on both the kinetic and potential energy in these ranges. The influence of the potential energy on particle emission is found to be stronger than the influence of the kinetic energy.