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Hydrogenated amorphous silicon (a-Si:H) devices on flexible substrates are currently being studied for application in dosimetry and beam flux measurements. The necessity of in vivo dosimetry requires thin devices with maximal transparency and flexibility. For this reason, a thin (<10 µm) a-Si:H device deposited on a thin polyimide sheet is a very valid option for this application. Furthermore, a-Si:H is a material that has an intrinsically high radiation hardness. In order to develop these devices, the HASPIDE (Hydrogenated Amorphous Silicon Pixel Detectors) collaboration has implemented two different device configurations: n-i-p type diodes and charge-selective contact devices.Charge-selective contact-based devices have been studied for solar cell applications and, recently, the above-mentioned collaboration has tested these devices for X-ray dose measurements. In this paper, the HASPIDE collaboration has studied the X-ray and proton response of charge-selective contact devices deposited on Polyimide. The linearity of the photocurrent response to X-ray versus dose-rate has been assessed at various bias voltages. The sensitivity to protons has also been studied at various bias voltages and the wide range linearity has been tested for fluxes in the range from 8.3 × 107 to 2.49 × 1010 p/(cm2 s). [ABSTRACT FROM AUTHOR]

X-ray fluorescence (XRF) is often used to detect metal content in soil. We’ve developed a soil heavy metal batch online detection system for efficiently analyzing large quantities of soil samples. The system comprises an OSADS (Online Soil Automatic Detection System), a custom-built XRF spectrometer, and an online data management platform. The XRF spectrometer, equipped with a low-power X-ray tube and a silicon drift detector, is controlled by an analysis controller to process signals. Data transmission is facilitated by an NB-IoT module. The OSADS platform, driven by a six-axis screw mechanism, integrates FreeRTOS on an STM32 controller for precise control. A specially designed soil sample tray simplifies sample handling, while the XRF spectrometer mounted on a sliding platform enables seamless testing. All data is uploaded to the server via the NB-IoT module. Our system significantly enhances soil sample detection efficiency and aids in data management. We’re open-sourcing this project to offer a rapid soil heavy metal detection solution. [ABSTRACT FROM AUTHOR]

Here, we present a high-sensitivity, rapid, and low-cost method for methane sensing based on a nonlinear interferometer. This method utilizes signal photons generated by stimulated parametric downconversion (ST-PDC), enabling the use of a silicon detector to capture high-precision methane absorption spectra in the mid-infrared region. By controlling the system loss, we achieve more significant changes in visibility, thereby increasing sensitivity. A low-cost CMOS camera is employed to capture spatial interference fringes, ensuring fast and efficient detection. Thereby, we demonstrate an accurate measurement of methane concentration within a gas cell. In addition, we show that ST-PDC enables long-distance sensing and the capability to measure open-path low ambient methane concentrations in the real world. [ABSTRACT FROM AUTHOR]

The Large Area Detector (LAD) is one of the science payloads of the enhanced X-ray Timing and Polarimetry (eXTP) mission. The LAD is a spectral-timing instrument with a broad energy response, covering a range from 2 to 30 keV, a good timing resolution of better than 10 µs, and an expected energy resolution of 260 eV at 6 keV. The LAD consists of 640 large-area multi-anode Silicon Drift Detectors (SDDs). Given the large number of detectors, the LAD uses a modular design. Each module comprises sixteen detectors, and each detector is equipped with dedicated Front-End Electronics (FEE), interfacing with two separate Module Back-End Electronics (MBEEs). Each MBEE is designed to process the data from 1,792 anode channels in 8 FEEs (224 anode channels per FEE), performing the energy reconstruction and time tagging for X-ray events. The MBEE uses the European Field Programmable Gate Array (FPGA) from NanoXplore™, based on a pipeline concept, which reduces dead time, making the LAD suitable for higher flux X-ray detection, and it can handle a sustained flux of >500 mCrab and a continuous flux of >15 Crab for up to 300 minutes (Feroci et al. 2018). Additionally, the MBEE serves as the central hub for configuring the module's electronics, including the FEEs, the Power Supply Unit (PSU), and the MBEE itself, and it is also responsible for collecting housekeeping data to monitor the system's status. The prototype MBEE was designed, manufactured, and programmed with FPGA firmware using VHDL. The basic functional test was conducted in this paper, and the results indicated that the MBEE could be operated in different modes to perform the functions mentioned above. Analysis and testing show that it can transmit event packets-containing timing tag, event type, position ID, and energy information-at a baud rate of 2 Mbps with an event loss fraction of 1.5%. [ABSTRACT FROM AUTHOR]

Among various silicon sensor technologies, 3D silicon sensors demonstrate significant potential for applications requiring exceptional radiation hardness and intrinsic high time resolutions. Silicon pixel sensors with columnar-type electrodes are already operational within the ATLAS experiment, serving in the previous Inner B-Layer (IBL) and the upcoming Inner Tracking (ITk) detectors. Concurrently, advancements driven by the next-generation LHCb VELO detector have led to the development of fast-timing 3D trench sensors within the INFN TimeSPOT project, achieving intrinsic time resolutions close to 10 ps. Remarkably, this performance is sustained even under irradiation levels far exceeding the expected limits for High Luminosity LHC operations. Despite these advantages, 3D trench sensors face challenges related to fabrication, as their production yields remain lower than those of the well-established columnar-type sensors. This highlights the necessity of designing a timing-optimized 3D sensor that leverages the robustness of a columnar electrode fabrication while achieving an intrinsic time resolution as close as possible to the trench-based designs. The design study addressed in this paper aimed to computationally compare the already designed and characterised TimeSPOT 3D trench sensor with alternative columnar electrode-based geometries, focusing particularly on configurations that approximate trench electrodes using parallel-oriented columnar designs. Different geometries and pixel sizes were designed, simulated, and compared. This work presents the entire design and selection effort as well as the preliminary layout of the selected pixel geometries, which are set to feature in FBK's upcoming production run in 2025. [ABSTRACT FROM AUTHOR]

A comprehensive study was performed to assess the detection capability of alpha spectrometry of water samples spiked with 239Pu and U-nat (234U, 235U, 238U) isotopes at activities below 100 mBq. Isotope dilution with the 236Pu and 232U tracers and radiochemical separations preceded alpha spectrometry using silicon detectors. The results were subjected to a variety of quantitative criteria and statistical significance tests to evaluate precision and accuracy of the results. State-of-the-art alpha spectrometry passed most of these tests as a robust and reliable radioanalytical technique for Pu and U determinations. [ABSTRACT FROM AUTHOR]

The Solar X-ray Detector (SXD) on-board the Macao Science Satellite-1B (MSS-1B) was successfully launched via the Chinese Long March-2C rocket on 21 May 2023, and commenced operations in early June of the same year. The MSS-1B/Soft X-ray Detection Units (SXDUs) employ two silicon drift detectors (SDDs), providing a wide range of energy spectra spanning from 0.7 to 24 keV. Notably, the SXDUs deliver a high-resolution capability of 0.14 keV@5.9 keV and operate with a time cadence of 1 second. Here, we perform thorough calibrations of the MSS-1B/SXDUs, employing a combination of ground experiments and simulations. In addition, quantitative analysis comparing the flux measurements obtained by the MSS-1B/SXDUs to the data collected by the Geostationary Operational Environmental Satellite (GOES), provides compelling evidence of their consistency. Furthermore, the preliminary spectral analysis results showcase the robustness and expected performance of the MSS-1B/SXDUs, unlocking their potential for facilitating the study of dynamic evolution of solar flares. Moreover, the innovative MSS-1B/Solar X-ray Detector facilitates concurrent observations of solar soft and hard X-rays, thereby making valuable contributions to the advancements in solar research. [ABSTRACT FROM AUTHOR]

The low-energy 19F(p, α )16O reaction has significant implications for nuclear astrophysics. The 19F(p, α )16O reaction occurs via three channels: (p, α 0 ), (p, α π ), and (p, α γ ). At lower temperatures, below 0.15 GK, the (p, α 0 ) channel is the dominant contributor of the reaction. The 19F(p, α 0 )16O reaction cross section in the energy range of 400–900 keV was studied in this work. Recent data in the literature reveals a roughly 1.4 increase compared to prior findings reported in the NACRE (Nuclear Astrophysics Compilation of REactions) compilation. Therefore, we present new additional result of the study published in EPJA [22] employing a silicon strip detector array (LHASA - Large High-resolution Array of Silicon for Astrophysics). The anguar distributions, the reaction cross sections and the astrophysical S-factors of the (p, α 0 ) channel were obtained through this experiment. Our findings resolve the discrepancies that exist between the two previously available data sets in the literature. [ABSTRACT FROM AUTHOR]

In this work, new vertex detector for the precision registration of D mesons was proposed for MPD experiment at NICA collider. This conception includes three cylindrical inner layers of large area thin (40–50 μm) silicon pixel sensors, bended around the collider beam pipe and located at a minimum distance from the interaction point of the beams. Also, detailed calculations of identification capability of this vertex detector, within the framework of the decays reconstruction of D+ and D0 mesons formed in central Au-Au collisions at the NICA collider energies, have been done. Using these estimates of D mesons reconstruction efficiency, the yields of such mesons in MPD experiment were obtained. [ABSTRACT FROM AUTHOR]

Background Purpose Methods Results Conclusions Carbon‐ion radiotherapy provides steep dose gradients that allow the simultaneous application of high tumor doses as well as the sparing of healthy tissue and radio‐sensitive organs. However, even small anatomical changes may have a severe impact on the dose distribution because of the finite range of ion beams.An in‐vivo monitoring method based on secondary‐ion emission could potentially provide feedback about the patient anatomy and thus the treatment quality. This work aims to prove that a clinically relevant anatomical change in an anthropomorphic head phantom may be detected via charged‐fragment tracking during a treatment fraction.A clinically representative carbon‐ion treatment plan was created for a skull‐base tumor in an anthropomorphic head phantom. In order to imitate an inter‐fractional anatomical change — for example, through tissue swelling or mucous accumulation — a piece of silicone was inserted into the nasopharynx. Fragment distributions with and without the silicone insert were subsequently acquired with a mini‐tracker made of four hybrid silicon pixel detectors. Experimental irradiations were carried out at the Heidelberg Ion Beam Therapy Centre (HIT, Germany). FLUKA Monte Carlo simulations were performed to support the interpretation of the experimental results.It was found that the silicone causes a significant change in the fragment emission that was clearly distinguishable from statistical fluctuations and setup uncertainties. Two regions of fragment loss were observed upstream and downstream of the silicone with similar amplitude in both the measurement and the simulation. Monte Carlo simulations showed that the observed signature is a consequence of a complex interplay of fragment production, scattering, and absorption.Carbon‐ion therapy monitoring with charged nuclear fragments was shown to be capable of detecting clinically relevant density changes in an anthropomorphic head phantom under realistic clinic‐like conditions. The complexity of the observed signal requires the development of advanced analysis techniques and underscores the importance of Monte Carlo simulations. The findings have strong implications for the ongoing InViMo clinical trial at HIT, which investigates the feasibility of secondary‐ion monitoring for skull‐base cancer patients. [ABSTRACT FROM AUTHOR]

ABSTRACT The artworks of the Archdiocesan Museum of Sacred Art of Rio de Janeiro (MAAS‐RJ) are distinguished for their combination of Luso‐Brazilian Sacred Arts and dedication to historical heritage preservation. An in situ analysis using x‐ray fluorescence (XRF) was conducted on five pieces from the collection, including Our Lady of the Expectation, Our Lady of Lapa, Our Lady of Penha de France, Saint Sebastian, and the Glory of the Divine. The analysis employed the portable Bruker Tracer‐III‐SD equipment, which features a Rhodium‐target x‐ray tube and a Silicon detector. Spectra were obtained with the device set at 40 kV and 35 μA, with a 60‐s exposure time. The multi‐element analysis identified the elements present in the pictorial layers, allowing the identification of pigments used in the original polychromes and repaints. The data revealed a diverse composition of pigments across the original, repainted, and polychrome regions. Elements indicative of pigments applied after the creation of the works, consistent with restoration and interventions, were detected. The XRF analysis confirmed the use of gilding techniques in some sculptures, such as Our Lady of the Expectation and the Glory of the Divine. The sculpture of Our Lady of Penha de France exhibited gilding techniques with sgraffito. This study provided the elemental composition of the examined sacred artworks, suggesting potential pigments regardless of their preservation conditions. [ABSTRACT FROM AUTHOR]

Solid-state detectors with a low energy threshold have several applications, including searches of non-relativistic halo dark-matter particles with sub-GeV masses. When searching for relativistic, beyond-the-Standard-Model particles with enhanced cross sections for small energy transfers, a small detector with a low energy threshold may have better sensitivity than a larger detector with a higher energy threshold. In this paper, we calculate the low-energy ionization spectrum from high-velocity particles scattering in a dielectric material. We consider the full material response including the excitation of bulk plasmons. We generalize the energy-loss function to relativistic kinematics, and benchmark existing tools used for halo dark-matter scattering against electron energy-loss spectroscopy data. Compared to calculations commonly used in the literature, such as the Photo-Absorption-Ionization model or the free-electron model, including collective effects shifts the recoil ionization spectrum towards higher energies, typically peaking around 4–6 electron-hole pairs. We apply our results to the three benchmark examples: millicharged particles produced in a beam, neutrinos with a magnetic dipole moment produced in a reactor, and upscattered dark-matter particles. Our results show that the proper inclusion of collective effects typically enhances a detector's sensitivity to these particles, since detector backgrounds, such as dark counts, peak at lower energies. The authors calculate the low-energy excitation cross section for relativistic feebly interacting particles scattering from silicon detectors. This enables a search for millicharged particles using data collected by the SENSEI detector and opens a new path for applications of low-threshold semi-conductor detectors to search for new physics. [ABSTRACT FROM AUTHOR]

The ASPECT-BET project, or An sdd-SPECTrometer for BETa decay studies, aims to develop a novel technique for the precise measurement of forbidden beta spectra in the 10 keV–1 MeV range. This technique employs a Silicon Drift Detector (SDD) as the main spectrometer with the option of a veto system to reject events exhibiting only partial energy deposition in the SDD. A precise understanding of the spectrometer's response to electrons is crucial for accurately reconstructing the theoretical shape of the beta spectrum. To compute this response, GEANT4 simulations optimized for low-energy electron interactions are used and validated with a custom-made electron gun. In this article we present the performance of these simulations in reconstructing the electron spectra measured with SDDs of a 109Cd monochromatic source, both in vacuum and in air. The allowed beta spectrum of a 14C source was also measured and analyzed, proving that this system is suitable for the application in ASPECT-BET. [ABSTRACT FROM AUTHOR]

Device simulation plays a crucial role in complementing experimental device characterisation by enabling deeper understanding of internal physical processes. However, for simulations to be trusted, experimental validation is essential to confirm the accuracy of the conclusions drawn. In the framework of semiconductor detector characterisation, one powerful tool for such validation is the Two Photon Absorption-Transient Current Technique (TPA-TCT), which allows for highly precise, three-dimensional spatially-resolved characterisation of semiconductor detectors. In this work, the TCAD framework Synopsys Sentaurus is used to simulate depth-resolved TPA-TCT data for both p-type pad detectors (PINs) and Low Gain Avalanche Detectors (LGADs). The simulated data are compared against experimentally measured TPA-TCT results. Through this comparison, it is demonstrated that TCAD simulations can reproduce the TPA-TCT measurements, providing valuable insights into the TPA-TCT itself. Another significant outcome of this study is the successful simulation of the gain reduction mechanism, which can be observed in LGADs with increasing densities of excess charge carriers. This effect is demonstrated in an p-type LGAD with a thickness of approximately 286 µm. The results confirm the ability of TCAD to model the complex interaction between carrier dynamics and device gain. [ABSTRACT FROM AUTHOR]

Background: In‐vivo monitoring methods of carbon ion radiotherapy (CIRT) includes explorations of nuclear reaction products generated by carbon‐ion beams interacting with patient tissues. Our research group focuses on in‐vivo monitoring of CIRT using silicon pixel detectors. Currently, we are conducting a prospective clinical trial as part of the In‐Vivo Monitoring project (InViMo) at the Heidelberg Ion Beam Therapy Center (HIT) in Germany. We are using an innovative, in‐house developed, non‐contact fragment tracking system with seven mini‐trackers based on the Timepix3 technology developed at CERN. Purpose: This article focuses on the implementation of the mini‐tracker in Monte Carlo (MC) based on FLUKA simulations to monitor secondary charged nuclear fragments in CIRT. The main objective is to systematically evaluate the simulation accuracy for the InViMo project. Methods: The implementation involved integrating the mini‐tracker geometry and the scoring mechanism into the FLUKA MC simulation, utilizing the finely tuned HIT beam line. The systematic investigation included varying mini‐tracker angles (from 15∘$15^\circ$ to 45∘$45^\circ$ in 5∘$5^\circ$ steps) during the irradiation of a head‐sized phantom with therapeutic carbon‐ion pencil beams. To evaluate our implemented FLUKA framework, a comparison was made between the experimental data and data obtained from MC simulations. To ensure the fidelity of our comparison, experiments were performed at the HIT using the parameters and setup established in the simulations. Results: Our research demonstrates high accuracy in reproducing characteristic behaviors and dependencies of the monitoring method in terms of fragment distributions in the mini‐tracker, track angles, emission profiles, and fragment numbers. Discrepancies in the number of detected fragments between the experimental data and the data obtained from MC simulations are less than 4% for the angles of interest in the InViMo detection system. Conclusions: Our study confirms the potential of our simulation framework to investigate the performance of monitoring inter‐fractional anatomical changes in patients undergoing CIRT using secondary nuclear charged fragments escaping from the irradiated patient. [ABSTRACT FROM AUTHOR]

The 3D trench silicon pixel sensors developed by the TimeSPOT collaboration have demonstrated exceptional performance, even after exposure to extreme radiation fluences up to 1 ⋅ 1 0 17 1 MeV n e q / cm 2 . This study assesses the radiation tolerance of these sensors using minimum ionizing particles during a beam test campaign. The results indicate that while radiation damage reduces charge collection efficiency and overall detection efficiency, these losses can be mitigated to levels comparable to non-irradiated sensors by increasing the reverse bias voltage. Charge multiplication was observed and characterised for the first time in 3D trench sensors, revealing a distinct operating regime post-irradiation achievable at bias voltages close to 300 V. Additionally, the timing performance of irradiated sensors remains comparable to their non-irradiated counterparts, underscoring their resilience to radiation damage. Currently, 3D trench silicon detectors are among the fastest and most radiation-hard pixel sensors available for vertex detectors in high-energy physics colliders. These findings highlight the potential of these sensors for new 4D tracking systems of future experiments at the Future Circular Hadron Collider (FCC-hh), advancing the capabilities of radiation-hard sensor technology. [ABSTRACT FROM AUTHOR]

Objective. The highly conformal carbon-ion radiotherapy is associated with an increased sensitivity of the dose distributions to internal changes in the patient during the treatment course. Hence, monitoring methodologies capable of detecting such changes are of vital importance. We established experimental setup conditions to address the sensitivity of a monitoring approach based on secondary-fragment tracking for detecting clinically motivated air cavity dimensions in a homogeneous head-sized PMMA phantom in 40 mm depth. Approach. The air cavities were positioned within the entrance channel of a treatment field of 50 mm diameter at three lateral positions. The measured secondary-fragment emission profiles were compared to a reference measurement without cavities. The experiments were conducted at the Heidelberg Ion-Beam Therapy Center in Germany at typical doses and dose rates. Main results. Significances above a detectability threshold of 2 σ for the larger cavities (20 mm diameter and 4 mm thickness, and 20 mm diameter and 2 mm thickness) across the entire treatment field. The smallest cavity of 10 mm diameter and 2 mm thickness, which is on the lower limit of clinical interest, could not be detected at any position. We also demonstrated that it is feasible to reconstruct the lateral position of the cavity on average within 2.8 mm, once the cavity is detected. This is sufficient for the clinicians to estimate medical effects of such a cavity and to decide about the need for a control imaging CT. Significance. This investigation defines well-controlled reference conditions for the evaluation of the performance of any kind of treatment monitoring method and its capability to detect internal changes within head-sized objects. Four air cavities with volumes between 0.31 cm3 and 1.26 cm3 were narrowed down around the detectability threshold of this secondary-fragment-based monitoring method. [ABSTRACT FROM AUTHOR]

The electronCT technique is an imaging method based on the multiple Coulomb scattering of relativistic electrons and has potential applications in medical and industrial imaging. It utilizes a pencil beam of electrons in the very high energy electron (VHEE, 50–250 MeV) range and a single detection layer for the determination of the beam profile. The technique constitutes a projectional, two-dimensional imaging method and thus also qualifies for the tomographic reconstruction of samples. Given the simplicity of the technical setup and its location behind the sample, the electronCT technique has potential synergies with VHEE radiotherapy, making use of the same electron source for both treatment and diagnostics and thus being a candidate for in situ imaging and patient localization. At the same time, several technical challenges arise from the measurement technique when applied for the imaging of living beings. Measurements performed at the ARES linear particle accelerator at an electron energy of 155 MeV using a mouse phantom and a Timepix3 silicon pixel detector assembly demonstrate the feasibility of this technique. Both projectional and tomographic reconstructions are presented and the potential and limits of the technology are discussed. [ABSTRACT FROM AUTHOR]

Self‐powered near‐infrared (NIR) photodetectors are essential for surveillance systems, sensing in IoT electronics, facial recognition, health monitoring, optical communication networks, night vision, and biomedical imaging. However, silicon commercial detectors need external power to operate and cooling to suppress large dark currents. This work demonstrates a new class of CMOS‐compatible self‐powered NIR photodetector based on ferroelectric 5‐nm thick ZrO2 films which do not require cooling and therefore have two key advantages over Si, and at the same time have comparable performance metrics. At room‐temperature, under 940 nm wavelength illumination (1.4 mW cm−2 power density, 10 Hz repetition rate), and without any power applied, fast rise and fall times of ≈2 and 4 µs, respectively, are achieved in Al/Si/SiOx/ZrO2/ITO devices, along with responsivity, detectivity and sensitivity values of up to ≈3.4 A W−1, 1.2 × 1010 Jones and 4.2 × 103, respectively, far exceeding all other emerging self‐powered systems. Furthermore, dual‐band NIR detection is shown for different NIR wavelengths, proof‐of‐concept feasibility being demonstrated for the smart identification of NIR targets. Therefore, it is demonstrated, for the first time, that coupling together the pyroelectric effect, the photovoltaic effect, and the ferroelectric effect is a novel method to significantly enhance the performance of CMOS‐compatible ZrO2‐based self‐powered photodetectors in the NIR region. [ABSTRACT FROM AUTHOR]

Low-Gain Avalanche Detectors are pivotal for the advancement of future nuclear, particle, and astroparticle experiments due to their exceptional fast timing capabilities and radiation hardness. Studying the performance of these detectors under adverse radiation environments is of significant importance, both from the fabrication and modelling point of view. This research aims to develop a reliable neutron-induced radiation damage model specifically for Low-Gain Avalanche Detectors using the technology computer-aided design simulator, Silvaco. The capabilities of the neutron damage model in Silvaco, originally developed by our group for pad detectors, are enhanced further by incorporating the acceptor removal mechanism, thus making it applicable to both thin and thick Low-Gain Avalanche Detectors. Validating this model is essential to ensure the reliability and performance of Low-Gain Avalanche Detectors in high-radiation environments, thereby supporting their integration into next-generation collider experiments. [ABSTRACT FROM AUTHOR]

The SIDDHARTA-2 experiment aiming at measuring for the first time the X-ray transitions in kaonic deuterium, has successfully completed its 2024 physics run at the DATNE collider of the INFN Laboratori Nazionali di Frascati. This work presents an overview of the scientific and technical achievements of SIDDHARTA-2 so far, including the most precise measurement of kaonic helium-4 La transitions and yields in gas, the observation of the kaonic helium-4 M-series transitions, and the measurement of high-n transitions in kaonic carbon, oxygen, nitrogen, and aluminium. The results of these measurements are discussed in the context of the kaonic atoms physics program at DA$NE, including future prospects within the EXKALIBUR proposal. [ABSTRACT FROM AUTHOR]

The radiation damage of 21 μ m thick self-biased epitaxial Δ E detectors were tested as a function of fluence of 90 MeV 14 N ions. Technology of production and technique of measurements of Δ E detectors were described. A new technique of soldering contact to thin detector is shown. In the present work the 21 μ m thick self-biased detectors marked as d4 and d5 show proper operation with the fluence about 4 · 10 15 ions/cm 2 and the fluence about 8 · 10 15 ions/cm 2 , respectively. The charge collection efficiency of thin d5 Δ E detector was increased about double at fluence about 8 · 10 15 ions/cm 2 . The charge collection efficiency of thin d4 Δ E detector was increased about 35 % at fluence about 4 · 10 15 ions/cm 2 followed decrease about 70 % of detector counting rate registration from fluence 9.1 · 10 15 ions/cm 2 to fluence about 5 · 10 16 ions/cm 2 due to partially removing of Al evaporated contact from detector surface as an effect of heavy ion irradiation. Increase of charge collection efficiency of thin self-biased detectors manufactured by the low-temperature technique was probably produced by increasing of build-in potential as an effect of activate carrier concentration of boron ions in epitaxial layer by heavy ion irradiation. [ABSTRACT FROM AUTHOR]

Photon-number resolving transition-edge sensors (TESs) with near unity system detection efficiency enable novel approaches to quantum computing, for example, heralding robust Gottesman–Kitaev–Preskill qubit states. Increasing the speed of the detectors increases the rate at which these states can be heralded. In addition, depending on the details of the scheme, faster detectors can reduce the complexities of the hardware implementation. In previous work, we demonstrated that adding a small amount of gold between the tungsten film and silicon substrate can increase thermal conductance and reduce detector recovery time. In that study, the readout electronics imposed limitations on stable biasing conditions of the TES detector, and the TES could only be biased at higher than ideal values. In this report, we demonstrate the operation of the TES illuminated by a heavily attenuated pulsed laser running at 1 MHz repetition rate and examine the limits to adding gold to speed up device recovery times using a higher bandwidth readout system. The best performance was achieved by combining a 15 × 15 μ m 2 tungsten TES with 5 μ m 3 of gold, which resulted in a recovery time faster than 250 ns, with an energy resolution of 0.25 eV full-width at half maximum at 0.8 eV photon energy. [ABSTRACT FROM AUTHOR]

Bulk γ‐InSe has a direct bandgap of 1.24 eV, which corresponds to near infrared wavelengths (λ = 1.0 µm) useful in optoelectronic applications from biometric detectors to silicon photonics. However, its potential for optoelectronic applications is largely untapped due in part to the lack of quantitative studies of its optical properties. Here, the unusually low absorptance and high photoluminescence quantum efficiency of single‐crystalline InSe flakes with thickness in the hundreds of nanometers are studied. InSe emits brightly at room temperature from its direct bandgap with a peak photoluminescence quantum yield (PLQY) of 20%, despite displaying indirect bandgap like low absorption coefficient due to the symmetry of its crystal structure. By performing pump‐dependent PLQY measurements, the radiative and nonradiative recombination coefficients are extracted, including the Shockley‐Read‐Hall and Auger coefficients. Finally, a proof‐of‐concept alternating current electroluminescent device at low temperature is demonstrated to show the promise of InSe in optoelectronic technology such as highly transparent, bright NIR light sources. [ABSTRACT FROM AUTHOR]

Sensitive mid‐infrared (MIR) spectroscopy plays an indispensable role in various photon‐starved conditions. However, the detection sensitivity of conventional MIR spectrometers is severely limited by excessive noises of the involved infrared sensors, especially for multi‐pixel arrays in parallel spectral acquisition. Here, an ultra‐sensitive MIR single‐pixel spectrometer is devised and implemented, which relies on high‐fidelity spectral upconversion and wavelength‐encoding compressive measurement. Specifically, a MIR nanophotonic supercontinuum from 3.1 to 3.9 µm is nonlinearly converted to the NIR band via synchronous chirped‐pulse pumping, which facilitates both the precise spectral mapping and sensitive upconversion detection. The upconverted signal is then spatially dispersed onto a programmable digital micromirror device, before being registered by a single‐element silicon detector. Consequently, the spectral information can be deciphered from the correlation between encoded patterns and recorded measurements, which results in a spectral resolution of 0.5 cm−1${\rm cm}^{-1}$ under an illumination flux down to 0.01 photons nm–1 pulse–1. Moreover, faithful reconstructions at sub‐Nyquist sampling rates are demonstrated using the compressive sensing algorithm, which leads to a 95% reduction in data acquisition time. The presented single‐pixel computational spectrometer features wavelength multiplexing, high throughput, and efficient sampling, which thus paves a new way for sensitive and fast spectroscopic analysis at the single‐photon level. [ABSTRACT FROM AUTHOR]

A R744 (CO 2) refrigeration system has been designed to cool down the Large Hadron Collider (LHC) silicon detectors ATLAS and CMS, located at CERN, Switzerland. The silicon detectors are subjected to high radiation levels. The system is composed of a pri- mary CO 2 trans-critical booster vapor compression loop operated with piston compressors, and an oil-free liquid pumped loop on the evaporation side, to preserve the detectors. To ensure the system's reliability, the cooling facility is designed to operate under a parallel operation mode of several modular 70 kW plant units providing evaporation temperature as low as -53 °C. This layout, is also useful in case of components failure and maintenance. A numerical model is developed using a dynamic simulation software Dymola that is based on the open source Modelica modelling language. The simulation results are proven on a first demonstration plant (System A) experimentally to explore the systems control logic and to validate the reliability of the system before it is built on the detectors side. In this paper the models development is explained and the results of the experimental validation of the numerical model are shown. [ABSTRACT FROM AUTHOR]

The Pauli exclusion principle (PEP), a cornerstone of quantum mechanics and whole science, states that in a system, two fermions can not simultaneously occupy the same quantum state. Several experimental tests have been performed to place increasingly stringent bounds on the validity of PEP. Among these, the series of VIP experiments, performed at the Gran Sasso Underground National Laboratory of INFN, is searching for PEP-violating atomic X-ray transitions in copper. In this paper, the upgraded VIP-3 setup is described, designed to extend these investigations to higher-Z elements such as zirconium, silver, palladium, and tin. We detail the enhanced design of this setup, including the implementation of cutting-edge, 1 mm thick, silicon drift detectors, which significantly improve the measurement sensitivity at higher energies. Additionally, we present calculations of expected PEP-violating energy shifts in the characteristic lines of these elements, performed using the multi-configurational Dirac–Fock method from first principles. The VIP-3 realization will contribute to ongoing research into PEP violation for different elements, offering new insights and directions for future studies. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to analyze black tattoo inks by means of energy dispersive spectroscopy and backscattered scanning electron microscopy. Methods: The sample consisted of five types of commercial tattoo pigments of the black colour (Easy Glow™, Electric Ink™, Iron Works™, Master Ink™, and Viper™). An Energy Dispersive Spectroscopy (EDS) detector (Silicon Drift Detector – SDD – type) attached to a Scanning Electron Microscope (SEM) device (Tescan Vega3 LMU, Libusina, Czech Republic) was used. X-ray characteristic signs were detected for each tattoo ink in an interval between 0 and 2.5 keV. The electron acceleration potential in the microscope was 15 keV. Two regions were analyzed for each sample (n = 10). On each region, a micrography of backscattered electrons (BSE) was obtained. Means and standard deviations (SD) of the weight percentages (Wt%) were calculated. Results: C and O were predominant, with a mean O/C ratio between 2.69 and 2.74 Wt%. Electric Ink and Master Ink were the most similar pigments, while Easy Glow was the most distinctive — with agglomerates of Al that had a concentration 25 × higher than other specimens. Other compounds detected in the sample were Cl and Cu. Conclusion: EDS and SEM were efficient to distinguish black tattoo inks. These are our preliminary outcomes on the use of EDS and SEM to analyze black tattoo inks. Thus, careful interpretation is necessary to avoid rash applications in human identification practice. [ABSTRACT FROM AUTHOR]

Background: The extremely fast delivery of doses with ultra high dose rate (UHDR) beams necessitates the investigation of novel approaches for real‐time dosimetry and beam monitoring. This aspect is fundamental in the perspective of the clinical application of FLASH radiotherapy (FLASH‐RT), as conventional dosimeters tend to saturate at such extreme dose rates. Purpose: This study aims to experimentally characterize newly developed silicon carbide (SiC) detectors of various active volumes at UHDRs and systematically assesses their response to establish their suitability for dosimetry in FLASH‐RT. Methods: SiC PiN junction detectors, recently realized and provided by STLab company, with different active areas (ranging from 4.5 to 10 mm2) and thicknesses (10–20 µm), were irradiated using 9 MeV UHDR pulsed electron beams accelerated by the ElectronFLASH linac at the Centro Pisano for FLASH Radiotherapy (CPFR). The linearity of the SiC response as a function of the delivered dose per pulse (DPP), which in turn corresponds to a specific instantaneous dose rate, was studied under various experimental conditions by measuring the produced charge within the SiC active layer with an electrometer. Due to the extremely high peak currents, an external customized electronic RC circuit was built and used in conjunction with the electrometer to avoid saturation. Results: The study revealed a linear response for the different SiC detectors employed up to 21 Gy/pulse for SiC detectors with 4.5 mm2/10 µm active area and thickness. These values correspond to a maximum instantaneous dose rate of 5.5 MGy/s and are indicative of the maximum achievable monitored DPP and instantaneous dose rate of the linac used during the measurements. Conclusions: The results clearly demonstrate that the developed devices exhibit a dose‐rate independent response even under extreme instantaneous dose rates and dose per pulse values. A systematic study of the SiC response was also performed as a function of the applied voltage bias, demonstrating the reliability of these dosimeters with UHDR also without any applied voltage. This demonstrates the great potential of SiC detectors for accurate dosimetry in the context of FLASH‐RT. [ABSTRACT FROM AUTHOR]

The Two-Photon Absorption–Transient Current Technique (TPA-TCT) is a device characterisation technique that enables three-dimensional spatial resolution. Laser light in the quadratic absorption regime is employed to generate excess charge carriers only in a small volume around the focal spot. The drift of the excess charge carriers is studied to obtain information about the device under test. Neutron-, proton-, and gamma-irradiated p-type pad silicon detectors up to equivalent fluences of about 7 × 1015  n eq / c m 2 and a dose of 186   M r a d are investigated to study irradiation-induced effects on the TPA-TCT. Neutron and proton irradiation lead to additional linear absorption, which does not occur in gamma-irradiated detectors. The additional absorption is related to cluster damage, and the absorption scales according to the non-ionising energy loss. The influence of irradiation on the two-photon absorption coefficient is investigated, as well as potential laser beam depletion by the irradiation-induced linear absorption. Further, the electric field in neutron- and proton-irradiated pad detectors at an equivalent fluence of about 7 × 1015  n eq / c m 2 is investigated, where the space charge of the proton-irradiated devices appears inverted compared to the neutron-irradiated device. [ABSTRACT FROM AUTHOR]

First proton production rates from the d(d,p)t reaction in the Mega Amp Spherical Tokamak Upgrade (MAST-U) are measured. The data were taken during the MAST-U experimental campaign with an upgraded version of the proton detector (PD) previously used in MAST. The new detector array consists of three collimated silicon surface barrier detectors with a depletion depth of 300 μm and a collimated 120 μm thick diamond detector, mounted on the MAST-U reciprocating probe arm. This array measures the energies of unconfined energetic 3 MeV protons and 1 MeV tritons mainly produced by beam-thermal DD reactions during neutral beam injection heating. Diamond detectors have the potential to be uniquely suited to detect charged fusion products as they promise to be much more radiation resistant and much less sensitive to temperature variations compared to silicon-based detectors. Using silicon and diamond-based detectors simultaneously allowed us to directly compare the performance of these two detector types. PD particle rates measured during different plasma scenarios are presented and compared to neutron rates measured using the neutron camera upgrade and TRANSP predictions. [ABSTRACT FROM AUTHOR]

Sterile neutrinos in the keV mass range present a viable candidate for dark matter. They can be detected through single β -decay, where they cause small spectral distortions. The Karlsruhe Tritium Neutrino (KATRIN) experiment aims to search for keV-scale sterile neutrinos with high sensitivity. To achieve this, the KATRIN beamline will be equipped with a novel multi-pixel silicon drift detector focal plane array named TRISTAN. In this study, we present the performance of a TRISTAN detector module, a component of the eventual 9-module system. Our investigation encompasses spectroscopic aspects such as noise performance, energy resolution, linearity, and stability. [ABSTRACT FROM AUTHOR]

Conventional silicon junction detectors encounter significant carrier recombination within the heavily doped p+ and n+ layers, as well as beneath the metal contact regions, creating the so-called "dead layers", especially on the detector side. In this study, we present the tunnel oxide passivating contact with doped polysilicon on oxide, which demonstrates exceptional surface passivation and carrier selectivity. The key innovation lies in an ultra-thin (~ 1.5 nm) interfacial oxide layer that facilitates efficient majority carrier transportation via tunneling while effectively block minority carriers. Remarkably low saturation current densities, ranging from 5 to 10 fA/cm2 even with the metal contact, underscore the superiority of both n-type and p-type tunnel oxide passivating contacts. In contrast, conventional p–n junction or high-low junction exhibit saturation current densities ranging from 10 to 90 fA/cm2 in the studied p+ and n+ layers with surface passivation schemes due to Auger recombination and surface recombination, and 1000–6000 fA/cm2 with metal contacts due to intense metal-induced recombination at the interface. These findings indicate the potential and superiority of implementing n-type tunnel oxide passivating contact on the detector side and p-type contact on the back side for advanced silicon radiation detectors. This approach would enable thorough collection of generated charge carriers along the track of incident ionizing radiation particles, leading to improved energy resolution and reduced noise levels. [ABSTRACT FROM AUTHOR]

Metal halide perovskites have shown unique advantages compared with traditional optoelectronic materials. Currently, perovskite films are commonly produced by either multi-step spin coating or vapor deposition techniques. However, both methods face challenges regarding large-scale production. Herein, we propose a straightforward in situ growth method for the fabrication of CsPbBr3 nanocrystal films. The films cover an area over 5.5 cm × 5.5 cm, with precise thickness control of a few microns and decent uniformity. Moreover, we demonstrate that the incorporation of magnesium ions into the perovskite enhances crystallization and effectively passivates surface defects, thereby further enhancing luminous efficiency. By integrating this approach with a silicon photodiode detector, we observe an increase in responsivity from 1.68 × 10−2 A/W to 3.72 × 10−2 A/W at a 365 nm ultraviolet wavelength. [ABSTRACT FROM AUTHOR]

Fluorine is one of the most interesting elements in nuclear astrophysics. Its abundance can provide important hints to constrain the stellar models since fluorine production and destruction are strictly connected to the physical conditions inside the stars. The F 19 (p,α)16O reaction is one of the fluorine burning processes and the correction evaluation of its reaction rate is of pivotal importance to evaluate the fluorine abundance. Moreover, the F 19 (p,α)16O reaction rate can have an impact for the production of calcium in the first-generation of Population III stars. Here, we present the AsFiN collaboration efforts to the study of the F 19 (p, α)16O reaction by means of direct and indirect measurements. On the direct measurements side, an experimental campaign aimed to the measurement of the F 19 (p, α 0 , π )16O reaction is ongoing, taking advantage of the new versatile arrays of silicon strip detectors, LHASA and ELISSA. Moreover, the Trojan Horse Method (THM) was used to determine the F 19 (p, α 0 )16O reaction S(E)-factor in the energy range of astrophysical interest ( E c m ≈ 0–1 MeV), showing, for the first time, the presence of resonant structures within the astrophysical energy range. THM has been also applied for the study of the F 19 (p, α π )16O reaction; data analysis is ongoing. [ABSTRACT FROM AUTHOR]

Characterization of the magnetic fields at different scales in the Universe is a new frontier for submillimeter astronomy. Polarimetric measurements between 50 and 500 µm are the golden path for this research. We develop, in the prospect of space observatories, all-silicon 50 mK bolometer arrays with polarimetric capabilities in the pixel. Here, we present the first results of the new detectors: performances of thermal sensors, optical absorption and polarimetry. [ABSTRACT FROM AUTHOR]

Background: Edge‐on‐irradiated silicon detectors are currently being investigated for use in full‐body photon‐counting computed tomography (CT) applications. The low atomic number of silicon leads to a significant number of incident photons being Compton scattered in the detector, depositing a part of their energy and potentially being counted multiple times. Even though the physics of Compton scatter is well established, the effects of Compton interactions in the detector on image quality for an edge‐on‐irradiated silicon detector have still not been thoroughly investigated. Purpose: To investigate and explain effects of Compton scatter on low‐frequency detective quantum efficiency (DQE) for photon‐counting CT using edge‐on‐irradiated silicon detectors. Methods: We extend an existing Monte Carlo model of an edge‐on‐irradiated silicon detector with 60 mm active absorption depth, previously used to evaluate spatial‐frequency‐based performance, to develop projection and image domain performance metrics for pure density and pure spectral imaging tasks with 30 and 40 cm water backgrounds. We show that the lowest energy threshold of the detector can be used as an effective discriminator of primary counts and cross‐talk caused by Compton scatter. We study the developed metrics as functions of the lowest threshold energy for root‐mean‐square electronic noise levels of 0.8, 1.6, and 3.2 keV, where the intermediate level 1.6 keV corresponds to the noise level previously measured on a single sensor element in isolation. We also compare the performance of a modeled detector with 8, 4, and 2 optimized energy bins to a detector with 1‐keV‐wide bins. Results: In terms of low‐frequency DQE for density imaging, there is a tradeoff between using a threshold low enough to capture Compton interactions and avoiding electronic noise counts. For 30 cm water phantom, 4 energy bins, and a root‐mean‐square electronic noise of 0.8, 1.6, and 3.2 keV, it is optimal to put the lowest energy threshold at 3, 6, and 1 keV, which gives optimal projection‐domain DQEs of 0.64, 0.59, and 0.52, respectively. Low‐frequency DQE for spectral imaging also benefits from measuring Compton interactions with respective optimal thresholds of 12, 12, and 13 keV. No large dependence on background thickness was observed. For the intermediate noise level (1.6 keV), increasing the lowest threshold from 5 to 35 keV increases the variance in a iodine basis image by 60%–62% (30 cm phantom) and 67%–69% (40 cm phantom), with 8 bins. Both spectral and density DQE are adversely affected by increasing the electronic noise level. Image‐domain DQE exhibits similar qualitative behavior as projection‐domain DQE. Conclusions: Compton interactions contribute significantly to the density imaging performance of edge‐on‐irradiated silicon detectors. With the studied detector topology, the benefit of counting primary Compton interactions outweighs the penalty of multiple counting at all lowest threshold energies. Compton interactions also contribute significantly to the spectral imaging performance for measured energies above 10 keV. [ABSTRACT FROM AUTHOR]

Background: There currently exists no widespread high dose‐rate (HDR) brachytherapy afterloader quality assurance (QA) tool for simultaneously assessing the afterloader's positional, temporal, transit velocity and air kerma strength accuracy. Purpose: The purpose of this study was to develop a precise and rigorous technique for performing daily QA of HDR brachytherapy afterloaders, incorporating QA of: dwell position accuracy, dwell time accuracy, transit velocity consistency and relative air kerma strength (AKS) of an Ir‐192 source. Method: A Sharp ProGuide 240 mm catheter (Elekta Brachytherapy, Veenendaal, The Netherlands) was fixed 5 mm above a 256 channel epitaxial diode array 'dose magnifying glass' (DMG256) (Centre for Medical and Radiation Physics, University of Wollongong). Three dwell positions, each of 5.0 s dwell times, were spaced 13.0 mm apart along the array with the Flexitron HDR afterloader (Elekta Brachytherapy, Veenendaal, The Netherlands). The DMG256 was connected to a data acquisition system (DAQ) and a computer via USB2.0 link for live readout and post‐processing. The outputted data files were analyzed using a Python script to provide positional and temporal localization of the Ir‐192 source by tracking the centroid of the detected response. Measurements were repeated on a weekly basis, for a period of 5 weeks to determine the consistency of the measured parameters over an extended period. Results: Using the DMG256 for relative AKS measurements resulted in measured values within 0.6%–3.0% of the expected activity over a 7‐week period. The sub‐millisecond temporal accuracy of the device allowed for measurements of the transit velocity with an average of (10.88 ± 1.01) cm/s for 13 mm steps. The dwell position localization for 1, 2, 3, 5, and 10 mm steps had an accuracy between 0.1 and 0.3 mm (3σ), with a fixed temporal accuracy of 10 ms. Conclusion: The DMG256 silicon strip detector allows for clinics to perform rigorous daily QA of HDR afterloader dwell position and dwell time accuracy with greater precision than the current standard methodology using closed circuit television and a stopwatch. Additionally, DMG256 unlocks the ability to perform measurements of transit velocity/time and relative AKS, which are not possible using current standard techniques. [ABSTRACT FROM AUTHOR]

The measurement of air quality, particularly the concentration of carbon dioxide (CO 2), has gained significant interest due to increased public health awareness. Elevated concentrations of CO 2 in the air have been linked to negative effects on cognitive functions and directly correlate with the quality of indoor air. This work presents the prototype of a miniaturized sensor module designed for sensing CO 2 concentrations in the air. The sensor module utilizes the two-chamber photoacoustic concept and features a compact design combining an absorption cell with a wafer-bonded detector based on silicon MEMS (micro-electro-mechanical systems) microphone technology. The CO 2 -filled detector chip uses the photoacoustic effect and is able to detect pressure oscillations within an enclosed volume generated by the absorption of modulated infrared (IR) light by CO 2 molecules. The complete sensor module measures only 9×13×7.8 mm 3 and the used detector chip is the smallest detector for two-chamber photoacoustic sensors reported to date. Experimental characterization showed that the prototype achieves a detection limit of 81 ppm CO 2 and exhibits a response time τ63 of 53 s. The compact size and performance characteristics make the proposed sensor module suitable for applications in indoor air quality monitoring. [ABSTRACT FROM AUTHOR]

Signal formation in a microstructured semiconductor neutron detector is more complex than in planar diode geometry. Three-dimensional microstructures are laterally smaller than the ionization cloud length, and the electric fields may be weak enough to exhibit plasma time effects. This work is the first detailed treatment of charge carrier motion in these complex semiconductor devices to replicate the time profile and signal magnitude. Simulations were performed using COMSOL Multiphysics to investigate various parameters that affect the propagation of the charge cloud. It was observed that the size of the simulated three-dimensional structure had an impact on the induced current pulse, indicating the importance of simulation geometry optimization to accurately simulate charge cloud expansion. COMSOL Multiphysics was used to replicate accurate charge creation profiles using energy deposition information imported from radiation transport codes. A detailed simulation methodology is presented to benchmark preamplifier event pulses along with complexities in modeling the charge carrier motion along the etched microstructured trenches with Si–SiO2 boundary conditions, including fixed oxide charge and interface trapping. [ABSTRACT FROM AUTHOR]