Aircrew exposure to cosmic radiation is recognised as occupational exposure in the European Union and is commonly evaluated using approved computational tools, including the Federal Aviation Administration (FAA) CARI code, which requires monthly values of the heliospheric modulation potential (hereafter HP; referred to as “heliocentric potential” in FAA documentation) and to date has been supplied exclusively by the FAA. We previously developed an independent European HP database reconstructed from count rates of the Lomnický štít 8NM64 neutron monitor (LMKS). The present study tests whether LMKS-derived HP values can replace FAA reference HP values as input to CARI7 within the ±20 % uncertainty band reported in the EURADOS inter-code comparison. CARI7 was run twice over 248,496 in-flight segments (latitudes 0–69◦ , altitudes 0–41,338 ft) under otherwise identical conditions, using only the HP source as the differing input, and the resulting pairs were compared for four CARI7 output quantities: 𝐷 Si , 𝐻*(10), 𝐸 (ICRP 60), and 𝐸 103 (ICRP 103). Across all four quantities the FAA → LMKS bias was 1.4–2.3 %, the 95 % limits of agreement stayed within ±11 %, Lin’s concordance correlation coefficient exceeded 0.990, two one-sided tests (TOST) accepted equivalence at 𝛿 = 5 % of the mean (𝑝 < 0.001), and 100 % of segments fell inside ±20 % in every one of 64 latitude × altitude bins. As an independent cross-check, residual distributions of Liulin-measured minus CARI7-computed dose from the CR10 onboard database were indistinguishable between potentials. The FAA → LMKS effect on effective dose (+2.16 %) is approximately four times smaller than the CARI6 → CARI7 model-version step (−8.88 %, 99.9 % of segments inside ±20 %). LMKS derived HP values are therefore interchangeable with FAA HP values for operational aircrew dosimetry.

We report systematic evidence that cold-season lightning in Central Eu- rope frequently occurs in close proximity to wind turbines. Using Blitzor- tung stroke data (2021–2024), ENTLN data (2023), and electric field mea- surements, we identify a recurring phenomenon - Seasonal Wind Turbine- Associated Lightning (SWAL), characterised by strokes clustering within proximity of wind turbines and exhibiting exclusively negative polarity. Elec- tric field observations show strong negative near-ground fields, suggesting that the lower positive charge layer is weak or absent and that the main negative charge region becomes exposed. These results raise the broader question of whether SWAL would occur in landscapes without wind tur- bines, or whether such episodes would otherwise fail to develop into fully formed winter thunderstorms.

Recently presented measurements of terrestrial gamma ray flashes (TGFs) above thunderstorms on board aircraft and weather balloons introduce viable alternatives which could help to overcome limitations inherent in satellite-based observations, such as gamma ray attenuation by the atmosphere and large distance between TGF source and detectors. This study explores the potential and implications of measuring TGFs using aircraft and weather balloons. Utilizing Monte Carlo simulations with the MCNP6 tool, the spatial distributions, fluences, and energy spectra of photons, electrons, and neutrons generated by TGFs are assessed at altitudes of 5 to 50 km. The results indicate that TGFs originating at lower altitudes produce narrower beams compared to those at higher altitudes, suggesting that weather balloons may be more effective for high-altitude TGFs, such as those associated with summer thunderstorms or thunderstorms in tropical regions, whereas staffed aircraft might be more suitable for low-altitude TGFs originating in temperate regions or in winter thunderstorms. Features of the photon and electron energy spectra, such as maximum energy and the presence of 511 keV photons, can help estimate the radial distance from the TGF axis. Expected photon fluences from TGFs reach up to 1000 cm-2, with electron fluences reaching up to 100 cm-2, depending on the TGF's brightness. Neutron fluences are notably lower, up to 1 cm-2. These findings underscore the potential of aerial and balloon-based measurements in providing critical insights into TGFs and their detection, addressing the limitations of current satellite observations.

In the European Union, radiation exposure of aircrew to cosmic radiation is classified as occupational exposure and must be routinely assessed. Personal doses are typically calculated using dedicated software tools. In Slovakia and Czechia, aircrew doses are commonly evaluated using the Federal Aviation Administration (FAA) CARI code, which is freely available and widely accepted. A limitation of CARI is its reliance on monthly values of the heliospheric modulation potential (hereafter HP; referred to as “heliocentric potential” in FAA documentation), which are currently provided exclusively by the FAA and derived from neutron monitor observations. The purpose of this work is to establish an independent European source of HP values based on measurements from the Lomnický štít standard 8NM64 neutron monitor (commonly referred to as LMKS, 2634 m a.s.l., vertical cutoff rigidity 3.84 GV). We present the methodology for deriving HP from LMKS data, evaluate candidate regression models against FAA reference values, and assess the statistical performance and operational applicability of the selected model. The results demonstrate that LMKS data provide a reliable basis for HP reconstruction and may support operational applications, including flight planning and optimization of crew radiation protection.

Electric Field Mills (EFMs) are critical tools in atmospheric sciences for measuring electric fields within thunderstorms. Traditional EFMs primarily record field magnitudes and often lack the precise temporal resolution and directionality necessary for in-depth storm analysis. Our research introduces THUNDERMILL01, an advanced EFM that determines both the magnitude and direction of electric fields, significantly enhancing temporal resolution. This study details the deployment of THUNDERMILL01 alongside a standard EFM at the Lomnický štít high-altitude observatory in Slovakia for comparative analysis. Initial findings indicate an enhanced capability to map charge distribution dynamics within thunderclouds, promising improvements in lightning prediction and thunderstorm understanding.

This study presents the first-ever published detection of two parallel winter continental gamma-ray glows in Central Europe, observed during a rare winter thunderstorm on Milešovka hill, Czech Republic. The combination of the hill's altitude of 837 m above sea level (a.s.l.) and the low altitude of the winter thunderstorm cloud resulted in an observation very near the acceleration region inside the thundercloud. The event was captured using a combination of advanced instruments, including a Ka-band cloud profiler (which enabled a detailed analysis of the storm's microphysics), a SEVAN large-area scintillation detector for monitoring ionizing radiation, and a staffed professional meteorological observatory. The radar data indicated the alignment of ice crystals within the cloud, strongly suggesting the presence of a substantial electric field. The findings offer valuable insights into winter thunderstorm dynamics in continental climates, with broader implications for studying high-energy atmospheric physics.

In this work, we analyzed simultaneous observations of solar particles and solar electromagnetic ultraviolet (UV) radiation during solar events from January 2024 to May 2024. Measurement campaigns to study the effects of space radiation on the terrestrial atmosphere were conducted in the framework of the project BIOSPHERE. We show the results of the campaign in Brussels from 1 January 2024 to 31 March 2024, during which several solar energetic particle (SEP) events were observed by the spacecraft GOES and OMNI, together with two big geomagnetic storms in March 2024 and May 2024 associated with solar eruptions. The last two events combine the arrival of a SEP event with a geomagnetic storm. On 11 May 2024, the biggest geomagnetic storm for the last 20 years was observed. These events enabled us to identify effects due to UV, solar particles, and geomagnetic storms. The impact of these events on the terrestrial radiation belts, illustrated by satellite observations like PROBA-V/EPT and on the atmospheric ozone using AURA/MLS is demonstrated. For the measurement campaign, muon and neutron monitors showed a Forbush decrease only during the geomagnetic storm at the end of March 2024 and in May 2024. Complemented by a simulation of radiation effects on the ionization rate of the atmosphere as a function of the altitude, the extensive range of different observations available during this measurement campaign demonstrated that SEP and geomagnetic storms due to solar eruptions had very different effects on the terrestrial atmosphere. The geomagnetic storms mainly modified the energetic electrons trapped in the space environment of the Earth and affected the ionization of the atmosphere above 60 km. They also modified the cosmic ray injections, mainly at high latitudes, creating Forbush decrease for the most intense ones. SEP events injected energetic protons in the atmosphere that could penetrate deeper in the atmosphere because they had more energy than the electrons. They could impact ozone, mainly at high altitude in the thermosphere. Solar activity variation associated with the rotation of the solar active regions in 27 days modulated UV. The measurements of these electromagnetic and particle radiations are crucial because they have important health implications.

This work presents the first measurement of the radiation field at the Allegra Laser for Acceleration (ALFA) at the ELI Beamlines laser-driven user facility. During the commissioning of ALFA laser pulses (< 20 fs, 1 kHz, 1.5 TW) were carefully focused inside supersonic gas targets to generate an ultra-short (fs) ultra-relativistic (10 s of MeV) electron beam. The radiation field produced was pulsed, mixed, and with high instantaneous fluxes and high dose rates. While new dosimetric techniques are being developed, important efforts are being made to investigate the behavior of known dosimetry systems at laser accelerators. The secondary radiation field at ALFA was here characterized using a combination of different solid-state dosimetric systems: optically stimulated luminescence, thermoluminesce, and radiophotoluminescence dosimeters. Luminescence dosimeters offer several advantages for these applications. They are robust and relatively inexpensive. They can be easily adapted to be placed in vacuum and comply with clean room environment: important aspects when laser optics are involved. Compared to active systems, there are no electronics that require shielding from electromagnetic pulses present at laser-driven accelerators. This contribution presents the obtained experimental data focusing on the different detector responses and their suitability for measurements at laser-driven accelerators.

Thunderstorm-induced gamma radiation phenomena, including terrestrial gamma-ray flashes (TGFs) and thunderstorm ground enhancements (TGEs), have emerged as key areas in high-energy atmospheric physics due to their potential radiation effects in the atmosphere. The interaction of high-energy photons and relativistic electrons with the air can lead to complex radiation processes, influencing local and global atmospheric radiation fields. Developing specialized gamma-ray spectrometers is essential in regions like Central Europe, where environmental and technical challenges differ from those in Japan or Asian high-altitude areas. This paper describes the necessary adaptations for gamma spectrometry in such environments, focusing on sensitivity to high-energy photon detection, rapid event timing, and integration into distributed measurement networks. Results from field deployments at high-altitude observatories and thunderstorm chase events provide new insights into the radiation dynamics of TGEs, contributing to a better understanding of radiation effects in the air during thunderstorms in continental climates.

The temporal variations of cosmic-ray intensity, measured by ground-based detectors at various latitudes, longitudes, and altitudes, are related to the geophysical and solar phenomena. The latter are interplanetary coronal mass ejections and fast solar wind from coronal holes, which cause interplanetary magnetic field (IMF) abrupt variations near Earth. Interacting with the magnetosphere, they cause worldwide sudden decreases (Forbush decreases, FDs) of intensity followed by gradual recovery. The amplitude of the flux depletion depends on the type and energy of the registered particle, which in turn depends on geographical coordinates and the detector's energy threshold and selective power. SEVAN particle detector network with nodes in Europe and Armenia selects three types of particles that demonstrate coherent depletion and recovery and correspond to different energy galactic protons interacting with disturbed magnetospheric plasmas. On November 3-4, 2021, an interplanetary coronal mass injection (ICME) hit the magnetosphere, sparking a strong G3-class geomagnetic storm and auroras as far south as California and New Mexico. All detectors of the SEVAN network have registered an (FD) of approximate to 5% depletion in a 1-min time series of count rates. Approaching the maximum solar activity cycle, large variations of the particle flux intensity were registered on February 27, March 23, 2023, and March 24, 2024. In this work, we present measurements of these FDs performed on mountain altitudes on Aragats (Armenia), Lomnicky Stit (Slovakia), Mileshovka (Czechia), and at sea level DESY (Hamburg, Germany). We compared FD measurements made by SEVAN detectors and neutron monitors located on Aragats and Lomnicky Stit and made a correlation analysis of FD registration at different locations.

This review explores current experimental methods for determining the radiation quality in ion beams. In this context, radiation quality is commonly evaluated using the averaged linear energy transfer (LET), a metric employed to assess the response of both biological and physical systems. Dose and averaged LET can be experimentally determined with passive detectors through various techniques that have seen recent improvements. Another metric related to the LET is the mean lineal energy, which is measurable using microdosimetric detectors. This review focuses on the available possibilities for evaluating the radiation quality using three microdosimeters (mini-TEPC, Silicon Telescope, and SOI Microplus), three passive luminescence detectors (based on optical, thermo-, and radiophoto-luminescence), three track-based detectors (track-etched detector, Timepix, fluorescent nuclear track detector), and a chemical detector based on alanine. A comparison of detector properties is provided along with an overview of the underlying mechanisms enabling LET assessment or measurements of the mean lineal energy with each detector type. Finally, this review summarizes the current possibilities of LET determination with respect to the needs for quality assurance in particle therapy. Areas for future research and development are suggested.

Download This Paper Open PDF in Browser Add Paper to My Library Share: Permalink Using these links will ensure access to this page indefinitely Copy URL Copy DOI

ELI Beamlines is one of the pillars of the Extreme Light Infrastructure European Research Infrastructure Consortium (ELI ERIC), the European project aiming at building the next generation of high power lasers for fundamental research and industrial applications. Several high-power lasers are hosted by the ELI Beamlines facility. Even at a power lower than the nominal one, when interacting with a target, the laser can generate mixed ionizing radiation fields of unique nature. One of the major laser systems, High-repetition-rate advanced petawatt laser system (HAPLS) was already used in commissioning experiments. Detecting the neutrons generated during these experiments has been a challenging task, since certain difficulties were faced. First, the experimental conditions were frequently altered during the commissioning phase (such as laser beam parameters, experimental geometry or target type). Next, the extremely short duration of the ionizing radiation pulse generated by the laser (~10-14 s) complicated the correct interpretation of the data provided by the detectors designed and calibrated in standard fields. Here, one commissioning experiment is described, together with the means of addressing the problem of the detection of the ionizing radiation and the lessons learned in this endeavour.

Polar regions are the most exposed to secondary particles and radiation produced by primary cosmic rays in the atmo-sphere, because naturally they are with marginal geomagnetic shielding. In addition, the secondary particle flux con-tributing to the complex radiation field is enhanced at high-mountain altitudes compared to sea level because of the reduced atmospheric attenuation. At present, there are very few systematic experimental measurements of environmental dose at high southern latitudes, specifically at high-altitude region. Here, we report a campaign of mea-surements with different devices, that is passive and Liulin-type dosimeters, of the radiation background at high -mountain Antarctic station Vostok (3488 m above sea level, 78 & DEG; 27 & PRIME; S; 106 & DEG; 50 & PRIME; E). We compare the measurements with a Monte Carlo-based model for the propagation of the cosmic rays through the atmosphere and assessment of the radiation field in the atmosphere. We employed the model to estimate the radiation dose at Vostok station during the ground-level enhancement at 28 October 2021. As in previous studies by other teams, we show that the annual dose equivalent at high-altitude Antarctic facilities can significantly exceed the limit of 1 mSv established for the gen-eral population by the ICRP.

This article describes the equipment (and the advantages of the equipment) used for in situ ground measurements of thunderstorm phenomena with measuring cars. By using all-sky high-speed cameras, radio receivers, and electric field measurements, typical lightning discharges in the central European region have been characterized. Measurements of ionizing radiation during storms using a gamma spectrometer were also performed. At ground level, no ionizing radiation originating from storm clouds was detected, although during other experiments (using the same equipment at lower altitudes corresponding to the lower part of storm clouds) ionizing radiation was detected. We showed that radio antennas with appropriately constructed receivers and all-sky high-speed cameras are devices that can significantly contribute to the understanding of processes taking place in storm clouds during lightning discharges. On the contrary, measurements of the vertical electric field did not provide any new information about the processes occurring in thunderclouds.

Measurements and theoretical studies show that thunderclouds can act as particle accelerators in nature. Terrestrial gamma ray flashes (TGFs) are bursts of gamma rays with energies ranging from below 10 keV to above 40 MeV, which last for microseconds to several milliseconds, and coincide with lightning produced in Earth's atmosphere. The gamma-ray spectra of TGFs are consistent with bremsstrahlung from energetic electrons going upward into space. More recently, similar phenomena but beamed downward have been discovered by ground-based observations: short bursts, “downward TGFs”, with durations of milliseconds and long bursts, “thunderstorm ground enhancements” (TGEs) or gamma ray glows, with durations up to several minutes. These findings have established a new academic field called “high-energy atmospheric physics”. The origin, and exact mechanisms creating the thunderstorm radiation (TGFs and TGEs), are still unclear but it has been suggested that TGFs are caused by intense electric fields produced above or inside thunderstorms. To explain TGF, electrons which are traveling at speeds very close to the speed of light collide with atomic nuclei in the atmosphere and release their energy in the form of X-rays (bremsstrahlung). Large populations of energetic electrons can be formed by avalanche growth driven by electric fields, a phenomenon called relativistic runaway electron avalanche (RREA). Airplane crew and passengers flying near thunderstorms could therefore be exposed to “dangerously” high levels of radiation in the form of short terrestrial y-ray flashes and little longer y-ray glows. To clarify the origin of TGFs, and to evaluate the absorbed dose of thunderstorm radiation, the project CRREAT (Research Centre of Cosmic Rays and Radiation Events in Atmosphere) measures both the lightning and the ionizing radiation during thunderstorms using detection instrument mounted on the roofs and inside of cars, and with ionizing radiation detectors installed on high mountains. One other important research area of CRREAT is measurements and simulations of the radiation field at aviation altitudes and at low earth orbits (LEO), since this poses a health risk for crew members and passenger's onboard aircraft and spacecraft. This paper gives an overview of possible sources of ionizing radiation and phenomena during thunderstorm.

When primary space radiation particles enter into the atmosphere of the Earth, they generate showers of secondary radiation. The intensity of secondary radiation reaches its maximum, called the Regener-Pfotzer maximum; its exact position depends on the geomagnetic effective vertical cut-off rigidity, the phase of the solar cycle and also on the type of detected particles. In this paper, several balloon flight experiments are described focusing on the study of the latitudinal effect on the position of the Regener-Pfotzer maximum. Altitude profile of ionization in the atmosphere was measured using radiation detectors flown during several flights at locations with different effective vertical cut-off rigidities (flight HEMERA over Sweden and flights FIK-5 and FIK-6 over Czech Republic). The measured results are supplemented also with simulations using EXPACS 4.11 and the variation of obtained positions of Regener-Pfotzer maximum is discussed.

The objective of this paper is to provide an overview of the current status in neutron personal dosimetry based on poly allyl diglycol carbonate (PADC), also commonly known by the commercial name CR-39, to summarize the best practices in the field, and to point future research directions. An overview of the fundamentals of the technique is given, including a discussion on the PADC material, main parameters and characteristics, practical considerations, dosimetry approaches, and relevant standards. This work also summarizes the best practices adopted by individual monitoring services (IMSs) and discusses the research needed to improve the performance of this type of neutron dosimetry technique, as well as the challenges that make progress difficult. This work is based on the knowledge and experience of several laboratories and investigators and is part of the activities of the European Radiation Dosimetry Group (EURADOS) Working Group 2 –Harmonization of Individual Monitoring in Europe (WG2).

UHDpulse - Metrology for Advanced Radiotherapy using beams with Ultra-High Pulse Dose Rates is a European project aimed at developing novel dosimetry standards, as well as improving existing ones, for FLASH radiotherapy, very high energy electrons radiotherapy, and laser-driven medical accelerators. Within the scope of this project, Thermoluminescence (TL) and Optically Stimulated Luminescence (OSL) detectors are used to measure stray radiation fields. Experiments performed with conventional pulsed particle-beams allow to characterize the dosimeters in known and controllable radiation fields. In turn, this allows to develop models and predict their behavior in complex radiation fields, such as those at laser-driven and FLASH facilities. TL and OSL detectors were irradiated at the Microtron MT25 electron accelerator in Prague, Czech Republic. GAFChromicTM films and plastic nuclear track detectors were used to study the beam profile and the neutron background respectively. The responses of the different detector to the pulsed mixed radiation fields of the Microtron MT25 are compared among each other and presented in this paper.