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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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Lomnický štít, Slovakia, 2634 m above sea level, is known to be a place of extreme electric fields measured during thunderstorms and is thus a suitable place for thunderstorm-related ionising radiation research. We present one of the strongest Thunderstorm ground enhancements (TGE) ever detected, which occurred on 12 September 2021. The TGE was detected with the SEVAN detector and also with the new Georadis RT-56 large volume gamma spectrometer. In the paper, we present spectra of the TGE measured with the spectrometer as well as SEVAN coincidence data supplemented by the data from electric field mill. [ABSTRACT FROM AUTHOR]

Stratospheric balloons are a useful tool for the investigation of cosmic radiation at high altitudes and the tests of new detectors of cosmic radiation. Due to necessary data processing, the balloon gondola needs to carry, together with radiation detectors, additional supplementary sensors measuring humidity, temperature, location and orientation, altitude, atmospheric pressure, acceleration, etc. A newly developed universal system TF-ATMON, based on using already existing tools of the PX4 open-source project, enables apart from data recording and monitoring, also the possibility to trace the balloon gondola after the flight. The application was demonstrated on stratospheric balloon flight FIK-6. This flight was unique because three different types of radiation detectors were used at one flight. It enabled us to compare the altitude of the Regener–Pfotzer maximum measured with different types of sensors sensitive to a different type of secondary cosmic radiation generated in the atmosphere. [ABSTRACT FROM AUTHOR]

The Microtron MT25 is a cyclic electron accelerator with a Kapitza resonator, maximum beam energy of 25 MeV, standard repetition frequency of 423 Hz, pulse length of 3.5 μs and mean current of 30 μA. Studies at conventional particle accelerators allow to understand the response of dosemeters in known and controllable radiation fields. Subsequently, it is possible to develop models and predict their behavior in complex radiation fields, such as those generated at laser and FLASH facilities. Therefore, response of thermally and optically stimulated luminescence detectors outside of the beam was studied at the Microtron MT25. The detectors were placed on a Plexiglas phantom inside a lead and iron bunker to shield-off background radiation. In addition, GAFChromic™ films and track detectors were used. Two irradiations were performed: with and without an 8-cm thick polyethylene moderator. This paper presents a comparison of the responses of the different detection systems. [ABSTRACT FROM AUTHOR]

A new Open-Source dosemeter, SPACEDOS, has been developed for measurements of cosmic radiation on board spacecraft and small satellites. Its main advantages are that it is small and lightweight with low power consumption. It can be adjusted for specific applications, e.g. used in pressurized cabins of spacecraft or in vacuum environments in CubeSats or larger satellites. The open-source design enables better portability and reproduction of the results than other similar detectors. The detector has already successfully performed measurements on board the International Space Station. The obtained results are discussed and compared with those measured with thermoluminescent detectors located in the same position as SPACEDOS. [ABSTRACT FROM AUTHOR]

At the flight altitudes of modern airplanes, cosmic rays intensity is several times higher than on the Earth's surface. The radiation field is not constant in time and due to various effects, not routinely considered in calculations, the exposure can increase several times. Therefore, a continuous monitoring of radiation exposure on board is required. This article characterises newly developed detectors Airdos-C with diverse scintillation crystals. Unlike detectors based on a Si diode, which are commonly used for long-term measurements, these detectors can also be used for detection of high-energy gamma-rays generated in thunderstorms. For a correct interpretation of the measured data it is important to perform an energy calibration and to verify the detector response in known radiation fields. The results obtained with several radionuclide sources were analysed using mathematical statistics methods. The detectors were also exposed onboard aircraft under well-defined conditions. [ABSTRACT FROM AUTHOR]

Silicon detectors such as Liulin and AIRDOS are used for cosmic radiation measurements onboard aircraft. These measurements can be used for the verification of computer programs assessing aircraft crew radiation exposure. Recently performed intercomparison flights showed large variances of absorbed doses among individual detectors and significant differences between results of silicon detectors and computer programs. In order to explain for these differences, we have developed energy calibration method that can be performed on short flights. The method is based on cross-calibration of Liulin and AIRDOS deposited energy spectra with deposited energy spectra measured by Timepix which has superior detection properties in terms of energy resolution and the detection threshold. Moreover, the portion of dose which is omitted due to low sensitivity for low-energy deposits was calculated. The resulting absorbed dose rates at two intercomparison flights show significantly improved variation of results and better agreement with modelled absorbed dose rates. [ABSTRACT FROM AUTHOR]

Neutron detection using nuclear emulsions can offer an alternative in personal dosimetry. The production of emulsions and their quality have to be well controlled with respect to their application in dosimetry. Nuclear emulsions consist mainly of gelatin and silver halide. Gelatin contains a significant amount of hydrogen, which can be used for fast neutron detection. The addition of B-10 in the emulsion is convenient for thermal neutron detection. In this paper, standard nuclear emulsions BR-2 and nuclear emulsions BR-2 enriched with boron produced at the Slavich Company, Russia, were applied for evaluation of fast and thermal neutron fluences. The results were obtained by calculation from the presumed emulsion composition without prior calibration. Evidence that nuclear emulsions used in the experiment are suitable for neutron dosimetry is provided. [ABSTRACT FROM AUTHOR]

Long-term measurements using silicon radiation spectrometer Liulin on board commercial aircraft have been performed since 2001; results were put into a new database, which covers more than 4500 flights with more than 130 000 measurements. Methodology and tools were developed to normalize the data with respect to latitude and altitude and thus enable comparison with other radiation detectors and with model calculations. This capability is demonstrated using data from the neutron monitor at Lomnický štít. Instead of providing data files for individual measurement period, two software solutions are delivered. First is a web-based user interface for visualizing and downloading arbitrary time window of interest from the database hosted at http://cr10.odz.ujf.cas.cz. The second is a set of interactive Python notebooks available at GitHub. Those implement the calibration, normalization and visualization methods—so the outputs can be tailored to user needs. The software and data are provided under GNU/CC license. [ABSTRACT FROM AUTHOR]

Track-etched detectors are commonly used also for radiation monitoring onboard International Space Station. To be registered in track-etched detectors, the particle needs to meet several criteria—it must have linear energy transfer above the detection threshold and strike the detector's surface under an angle higher than the so-called critical angle. Linear energy transfer is then estimated from calibration curve from the etch rate ratio V that is calculated from parameters of individual tracks appearing on the detector's surface after chemical etching. It has been observed that V can depend on the incident angle and this dependence can vary for different detector materials, etching and evaluating conditions. To investigate angular dependence, detectors (Harzlas TD-1) were irradiated at HIMAC by several ions under angles from 0° to 90°. The correction accounting not only for critical angle but also for dependence of V on the incident angle is introduced and applied to spectra measured onboard International Space Station. [ABSTRACT FROM AUTHOR]

Aircrew members and passengers are exposed to increased rates of cosmic radiation on-board commercial jet aircraft. The annual effective doses of crew members often exceed limits for public, thus it is recommended to monitor them. In general, the doses are estimated via various computer codes and in some countries also verified by measurements. This paper describes a comparison of three cosmic rays detectors, namely of the (a) HAWK Tissue Equivalent Proportional Counter; (b) Liulin semiconductor energy deposit spectrometer and (c) TIMEPIX silicon semiconductor pixel detector, exposed to radiation fields on-board commercial Czech Airlines company jet aircraft. Measurements were performed during passenger flights from Prague to Madrid, Oslo, Tbilisi, Yekaterinburg and Almaty, and back in July and August 2011. For all flights, energy deposit spectra and absorbed doses are presented. Measured absorbed dose and dose equivalent are compared with the EPCARD code calculations. Finally, the advantages and disadvantages of all detectors are discussed. [ABSTRACT FROM AUTHOR]