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Two versions of a forward hodoscope have been developed and manufactured based on scintillation and radiation-resistant quartz plates. The hodoscopes are designed to register ions in the BM @ N experiment at the NICA accelerator complex. The light outputs and their inhomogeneity were measured as a function of the coordinates of the passage of particles through the hodoscope plates on the calibration beam of the secondary electrons of the “Pakhra” synchrotron of the Lebedev Physical Institute.

Designs of hodoscopes of nuclear fragments based on quartz and scintillation plates with light pickup by silicon avalanche photodiodes are described. Hodoscopes are planned for use in the BM@N experiment for registration of heavy nuclear fragments near the axis of the heavy ion beam. The results of measurements of light yields in detector elements based on quartz and scintillation plates on the electron beam of the synchrotron "Pakhra" (LPI) are presented. The measured nonuniformity of the light collection shows that readout from both sides of hodoscope detector elements is needed.

Forbush effects caused by powerful X-class solar flares are studied using URAGAN muon hodoscope data for the period 2007–2019. The URAGAN muon hodoscope registers the cosmic ray muon flux on the Earth’s surface from different directions simultaneously. This allows study of the energy, angular, and space–time characteristics of variations in the cosmic ray muon flux during Forbush effects. The dependence of the measured Forbush effects on the parameters of heliospheric and geomagnetic disturbances is analyzed.

An analysis is performed of the diurnal variation in cosmic-ray muons measured with the URAGAN muon hodoscope from 2007 to 2019. Characteristics are given of the yearly average diurnal variation in the count rate in several zenith-angle intervals. The results are compared to the diurnal variations in the count rate of neutrons from ten neutron monitors.

This paper offers a method for estimating the normalized instrument response function (IRF) of the URAGAN muon hodoscope (MH). A multiparametric model of the instrument response function is derived from digitally processed time series of MH matrix data and the hypothesis of muon-flux (MF) intensity distribution is formulated. Formulae for estimating the normalized instrument response function are devised and used in an algorithm for estimating normalized variations of functions in MF intensity. The algorithm was tested on simulated and experimental muon observation data.

The results of the calculations of coordinate resolution and hadron rejection factor for a simple e/gamma detector consisting of a lead convertor followed by a hodoscope are presented. For the simulation of showers, initiated in the converter by electrons and hadrons with energies upto 1 TeV GEANT4 is used. It is shown that the best coordinate resolution for electrons is achieved when the converter thickness is closed to the shower maximum. For example, at 200 GeV with 2 mm strip width hodoscope it is equal to sigma=89 microns provided a "truncated mean" coordinate estimation is used. The optimal thickness of the converter for hadron rejection is also close to tmax. For 200 GeV beam of electrons and protons the rejection factor of 10^-4 for 0.9 electron detection efficiency can be reached using only data on charged particles multiplicities. Information on the spatial distribution of the shower particles after the converter allows to enhance further the rejection by several times., Comment: 13 pages, 11 figures

Variations of secondary cosmic rays on the Earth’s surface depend on the solar activity. To study these variations, neutron monitors and muon detectors are used. Observations of muons and hadrons complement each other in terms of the energies of the primary cosmic rays and their angular distribution. Muons save the direction of the motion of primary particles and make it possible to obtain the angular distribution of cosmic ray modulations using a single setup—as a muon hodoscope. This paper presents a comparison of variations of muon and neutron components of cosmic rays at the Earth surface at different phases of the solar activity in the period from 2008 to 2018. For the comparison, data of two neutron monitors (Moscow and Apatity stations) and the muon hodoscope URAGAN were used.

Beam hodoscopes based on 32 × 32 square polystyrene scintillating fibres along X/Y, having section 3 × 3 mm2 or 1 × 1 mm2, have been designed and characterised for monitoring low-energy charged particle beams. Each fibre is read by a SiPM and the signal is digitised and analysed off-line. Hodoscopes were exposed to the 60 MeV/c negative muon beam at Port 1 of the RIKEN-RAL muon facility (UK), where they proved to be good to determine the beam profile and its intensity, via a calibration with cosmic muons. Furthermore, the exposition to the calibrated single-proton beam at CNAO (Italy), in the momentum range between 340 MeV/c and 690 MeV/c, provided further calibration in dE/dx and showed the feasibility of the detector as an instrument for proton beam characterisation too. These hodoscopes will be used as negative muon beam monitors for the FAMU experiment at the Rutherford Appleton Laboratory, but the possibility of using them as a beam monitor in hadron therapy has also been investigated.

A universal model is considered for a scintillation muon hodoscope (MH) to be used in the muonography of large objects. Muon tracks are registered by a multilayer assembly of narrow long scintillation strips with light collected by optical fibers on silicon photomultipliers. Characteristics of the scintillation MH are determined and its model in the Geant4 software package is described. The model strip’s parameters are calibrated on the basis of experimental data.

Cosmic ray muons are widely used to study the internal structure of different large-scale natural and artificial objects. The technique is called muonography in analogy with radiography. In this work, results are presented from tests of different elements of the detecting system of the muon hodoscope under development at MEPhI.

Cross-correlation between observation matrixes of the URAGAN muon hodoscope and the Dst index was studied. Functions of total intensity and anomaly were introduced. The results of calculations of cross-correlations on 2D diagrams were considered. It was shown that time periods with increased geomagnetic activity were almost always preceded by time periods with increased values of the modulus of the Pearson correlation coefficient.

A method for elimination of periodical diurnal, annual, and 27-day and 11-year solar variations in the matrix observations of the URAGAN muon hodoscope was developed. The analysis of the parameters of these variations in the time and frequency domains was performed. Two-dimensional bandpass filtering of sequences of muon hodoscope matrix observations was implemented. The structure of a two-dimensional filter is developed, based on the operation of elementwise matrix multiplications and additions. Examples of eliminating variations in the URAGAN muon hodoscope matrix observations are discussed.

The influence of a high-speed solar wind on the state of magnetosphere, as well as on the cosmic ray flux registered on the Earth’s surface by the muon hodoscope URAGAN (MEPhI) is discussed. The results of the analysis of the parameters of muon flux local anisotropy in the periods of low solar activity (2008–2009 and 2017–2018) during geomagnetic disturbances caused by the high-speed solar wind are presented.

This paper presents a method for identifying heliospheric anomalies using the introduced function of characteristic deviations for the muon hodoscope matrices. The estimation of the averaged hardware function is considered. Spatial filtering is proposed to eliminate fluctuations in the functions of the characteristic deviations. An example of the implementation of the developed method using the example of the storm July 13, 2017. It is shown that for this event, the identified anomaly precedes by several hours a sharp increase in the Kp index.

We present a study of the radiation field at various locations in the ATLAS experiment, using compact detector systems based on pixelated silicon sensors assembled with Timepix readout chips. The hodoscope design of the ATLAS-Timepix (TPX) detectors includes neutron converters in between two sensors, allowing the characterization of both neutron and charged particle fields on a track by track basis. Thermal and fast neutrons are discriminated by segmenting the sensor area with dedicated sensitive materials. Using specific pattern recognition algorithms, clusters from electrons and photons above ~10 keV, minimum ionizing particles (MIPs), and highly ionizing particles are classified. A coincidence method using the time-over-threshold mode of the chip is developed to extract stopping power and directional information of energetic charged particles. Thermal neutron fluences are obtained for each ATLAS-TPX unit, illustrating the effect of detector material and shielding in the experimental cavern. Reconstructed trajectories of energetic charged particles point out radiation coming from the interaction point and other hot spots.

The Baksan Underground Scintillation Telescope (BUST) is located in the North Caucasus in an underground laboratory at an effective depth of 850 m.w.e. The BUST began working in 1977, and the installation is still in operation. The successful design of the BUST allows it to be used to solve a number of problems in astrophysics and particle physics. The new data acquisition system is designed to record and analyze experimental data with greatly improved measurement characteristics of digital and analog signals. The data acquisition system is based on the VME interface and provides complete compatibility with existing low-level BUST recording electronics. The hodoscope of pulse channels was completely redeveloped and implemented on field-programmed gate array (FPGA) and LVDS chips.

We propose a method for determining the instrumental function of the URAGAN muon hodoscope based on the mathematical technique of Monte-Carlo simulation. Various components of the instrumental function simulate operation of the hodoscope and atmospheric reduction of muon flux intensities. We develop a technique for estimating the instrumental function of the hodoscope, and implement a statistical testing algorithm. We discuss applying the estimated instrumental function to various input models for the muon flux density distribution function.

Continuous monitoring of the muon flux over wide ranges of zenith and azimuth angles with the URAGAN detector (Moscow, 55.7° N, 37.7° E, 173 m AMSL) allows detection of variations in its intensity and angular distribution. A way of locating domains of anisotropy in the muon angular distribution is described, and they are mapped in matrix form in the GSE coordinate system. The maximum depth (height) of deformation, the zenith and azimuth angles of the center in the local system, and its GSE longitude and latitude are determined for each observed domain. The GSE longitudes of the detected domains of anisotropy are available on the Internet as functions of time and can be used to monitor the heliosphere’s activity.

This work describes the theoretical and experimental performances of four alternatives to the original Hornyak Button-type device that was used in the construction of the Transient Reactor Test (TREAT) Facility hodoscope. The alternatives considered differ in geometry, construction and detection materials to improve performance while decreasing some of the negative aspects of the original device. A Geant4 model of the original Hornyak Button was developed as a benchmark to validate the physics modeled, which agreed well with the reported values. The four alternatives considered were (1) a homogenized ZnS:Ag/PMMA rectangular bar outfitted with silicon photomultipliers (SiPMs), (2) a layered ZnS:Ag/PMMA rectangular bar detector also outfitted with SiPMs, (3) a microstructured neutron detector (MSND) backfilled with hydrogenous material and (4) a pressurized, organic gaseous scintillator. In two scintillation devices, SiPMs were considered as a replacement for photomultiplier tubes for greater light collection. These alternatives were considered as they each had the potential to provide better signal-to-noise ratios, reduce Cerenkov light production, increase detection efficiency, and/or improve neutron-to-gamma discrimination. At comparable lengths, the layered design has been experimentally determined to yield an efficiency of 1.3% (the Hornyak button exhibits 0.4%), while studies on the performances of the other detectors are still underway.

Presented is the numerical study of fast-sensitive, actinide and hydrogenous microstructured semiconductor neutron detectors (MSNDs) for the hodoscope at the Transient REActor Test facility (TREAT) using Geant4 and MCNP6. Neutron converters considered were 237Np, 235U, natural uranium, and 232Th for actinide MSNDs and paraffin wax for hydrogenous MSNDs (H-MSNDs). Paraffin wax was found to have a larger fission-spectrum-weighted macroscopic cross section (0.32 cm −1) than the actinide materials (the best being 0.067 cm −1 for 237 Np). However, actinide reactants were found to allow higher lower-level discriminator (LLD) settings due to the large energy of fission fragments. Actinide MSNDs filled with 235U, natural uranium, and 232Th were evaluated in Geant4 using the fission fragment generator. With the LLD set to 5 MeV, the intrinsic neutron-detection efficiency of the 235U-filled MSNDs was 1.2% for a 2-cm device length and saturated at 2.6% for lengths beyond 14 cm, where 20- μ m trench and 10- μ m wall widths were assumed. The deposited energy in 235U predicted by Geant4 differed from the MCNP6-predicted value by about −0.7%. With the LLD set to 300 keV, Geant4 and MCNP6 predicted an efficiency of about 10% for a 2-cm long H-MSND with 20- μ m trench and 10- μ m wall widths and an efficiency of about 26% for a detector length of 20 cm. For a LLD set to achieve a signal-to-noise (S/N) ratio of 100 when including gamma-ray noise, the best-case, Geant4-predicted efficiencies were 2.5% and 9.6% for 2-cm and 20-cm long devices with 60- μ m trench and 40- μ m wall widths.

The design and performance of a new front-end acquisition system is presented in this paper. It was developed to be used with muon array with resistive plate chamber (RPCs) for tagging air showers (MARTA’s) RPC detectors that measure the muonic component of cosmic ray air showers. The system is hybrid and capable of counting active channels and performing a charge measurement. It is low power (1.43 W per 64 channels), compact ( $21.6 \times 14.4\,\,\mathrm {cm^{2}}$ per 64 channels), stable, and reliable to comply with the strict demands of field operation associated with experiments that measure air showers. The front-end is based on an application-specified integrated circuit [Multi Anode Read-Out Chip (MAROC)] with 64 input channels, which is responsible for the digitization of the RPC signals. While a simple threshold measurement is applied after a fast shaper to count particles, the charge measurement is performed by an analog to digital converter that reads the peak of a slow shaper. An field-programmable gate array is responsible for control of all the digital part which includes storing the MAROC outputs and sending them to a Central Unit [via low voltage differential signal (LVDS)] or PC (via USB). Both the count and charge measurement performance are assessed. The threshold efficiency curve is measured for different temperatures. For all the conditions tested, the efficiency is 100% for charges higher than 52 fC. The overall efficiency to detect muons is studied by placing an RPC between a hodoscope and comparing the efficiency of the front-end with another established data acquisition system. The efficiency results are consistent within the statistical uncertainties of the measurements showing that the MARTA front-end does not introduce unwanted inefficiencies in the setup. The charge measurement is tested in the laboratory using a signal generator. Different shaping conditions and input charges are used to study the waveform of the slow shaper. A linear dependence between input charge and the value measured by the MAROC was found and taken as the calibration curve for the particular channel tested.

Coronal mass ejections (CMEs) are the brightest manifestations of solar activity. During periods of higher solar activity, dozens of ejections are observed daily and affect cosmic ray fluxes in interplanetary space. Observation of CMEs is usually carried out by means of various satellite apparatuses. In this work, features of the investigation of coronal mass ejections that are detected in the muon flux by the ground-based URAGAN muon hodoscope operating as a part of the Experimental complex NEVOD at the Moscow Engineering Physics Institute are discussed. Results of studying the anisotropy of the cosmic ray muon flux during the CMEs of 2016 are presented.

The method of flicker-noise spectroscopy is used for remote identification of geoeffective disturbances of the solar wind. The method is based on the study of short-term variations in the cosmic-ray flux that arise when it crosses the perturbed regions in the inner heliosphere. The magnitude of the effect is usually small and it is hidden in statistical noise. The analysis uses data from a continuous flux of secondary atmospheric muons. Bumps of the “nonstationarity” parameter of time series of muons indicate the emergence of advanced signals (predictors) 1–3 days before the disturbances enter the Earth’s magnetosphere. Geoeffective events with a low threshold (Ap > 30 nT) for various types of solar wind are analyzed. The results are obtained using a ground-based muon hodoscope URAGAN (Moscow). The technique can be used for continuous monitoring of space weather.

Problems of digital processing of Poisson-distributed data time series from various counters of radiation particles, photons, slow neutrons etc. are relevant for experimental physics and measuring technology. A low-pass filtering method for normalized Poisson-distributed data time series is proposed. A digital quasi-Gaussian filter is designed, with a finite impulse response and non-negative weights. The quasi-Gaussian filter synthesis is implemented using the technology of stochastic global minimization and modification of the annealing simulation algorithm. The results of testing the filtering method and the quasi-Gaussian filter on model and experimental normalized Poisson data from the URAGAN muon hodoscope, that have confirmed their effectiveness, are presented.

Muon flux intensity modulation (MFIM) recognition is a relevant solar-terrestrial physics problem. The MFIM discussed are due to geoeffective solar coronal mass ejections.The necessary observations are carried out using a computerized muon hodoscope (MH) URAGAN developed by NRNU MEPhI, registering muon fluxes intensity. In the MH, the number of muons falling on its aperture per unit time is counted. MH matrix data time series are formed, in which angular and temporal modulations take place due to MH design features, athmospheric disturbances and noises, the values of which significantly exceed the MFIM values.The MFIM recognition method based on the mathematical apparatus of indicator matrices (IM) and spatial-temporal filtering is proposed.The time series of MH matrix data, consisting of a set of Poisson processes corresponding to azimuthal and zenithal elements of MH matrices, are considered.A reference time span is assigned where MFIM are known to be missing. For it, matrices of estimates of mathematical expectations are calculated and, taking into account the Poisson property, the matrices of reference confidence intervals are calculated. Next, the current time sections are formed, on which the matrices of the current confidence intervals are calculated. Based on the comparison of the matrices of the reference and current confidence intervals, the current matrices of anomalies are formed, which are compared with the specified threshold matrix. Thresholds exceedings correspond to anomalous events. Binary IM are formed: ones correspond to anomalous events, zeros correspond to the absence of anomalies. Recognition is to analyze IM sequence and identify areas of non-zero elements condensation that lead to the conclusion that there are significant MFIM. To reduce the recognition errors, the space-time IM filtering has been developed.MFIM recognition technique, based on the use of IM time series with spatial-temporal filtering has been tested on model and experimental MH data.Testing on the generated time series of model Poisson MH matrix data with model MFIM confirmed the conclusion about the possibility of MFIM recognition by the proposed method with a decrease level of 3-4%. Application of spatial-temporal filtering made it possible to recognize MFIM with decreases with a level half as much.Testing on the formed experimental matrix MH data time series with model MFIM led to a conclusion that it is possible to recognize MFIM with the magnitudes of decreases almost commensurate with the decreases for the case of model MH data.The proposed MFIM recognition method based on indicator matrices for MH observation data allows optimization of parameters and can be successfully applied to solve problems of MFIM recognition and early diagnostics of geomagnetic storms.

Muon flux intensity modulation (MFIM) recognition is a relevant solar-terrestrial physics problem. The considered MFIM, recorded on the Earth's surface, are caused by extreme heliospheric events – the geoeffective solar coronal mass ejections.The URAGAN muon hodoscope (MH), developed by NRNU MEPhI, a computerized device that measures the intensities of muon fluxes, is used. In the MH, the number of muons falling per unit time on the MH aperture is calculated for the selected system of zenith and azimuthal angles. MH matrix data time series are formed. In the MH data, there are angular modulations due to the action of the hardware function HF, temporal modulations due to atmospheric disturbances and noise: the values of these modulations significantly exceed the values of MFIM of cosmic origin. This circumstance prevents effective MFIM recognition.A method for MFIM recognition is proposed, based on the mathematical apparatus of the introduced normalized variation functions for MH matrix data, and focused on overcoming the noted circumstance.A two-dimensional normalized HF is defined for MH. A quite realistic hypothesis is accepted about the initialiy uniform muon flux intensity distributions on a small reference time interval, where there are no extreme heliospheric events and the corresponding reference MH data do not contain significant MFIMs. The estimation of the two-dimensional normalized HF is carried out on the basis of a multiparameter model and its optimization fit to the reference MH data. In order to reduce noise errors, the estimate of the two-dimensional normalized HF is subjected to two-dimensional filtering and subsequent threshold filtering.Two-dimensional functions of variations of matrix MH datas with respect to two-dimensional normalized AF are calculated. The normalized variation functions are calculated by dividing the two-dimensional functions of variations of matrix MH data by the two-dimensional normalized HF. MFIM recognition method was tested on model and experimental MH data.A time series of model matrix MH data containing model MFIM was generated. Testing led to a conclusion that it is possible to recognize MFIM with decreases of about 2-3%. A time series of experimental matrix MH data was generated, in which the model MFIM-containing areas were made. Testing led to a conclusion that it is possible to recognize MFIM with the magnitudes of the decreases almost commensurate with the decreases for the case of model MH data.The proposed MFIM recognition method based on the normalized variation functions for matrix MH data has a favorable perspective for its application in solving problems of geomagnetic storm early diagnostics.

The GlueX experiment at Jefferson Lab has been designed to study photoproduction reactions with a 9-GeV linearly polarized photon beam. The energy and arrival time of beam photons are tagged using a scintillator hodoscope and a scintillating fiber array. The photon flux is determined using a pair spectrometer, while the linear polarization of the photon beam is determined using a polarimeter based on triplet photoproduction. Charged-particle tracks from interactions in the central target are analyzed in a solenoidal field using a central straw-tube drift chamber and six packages of planar chambers with cathode strips and drift wires. Electromagnetic showers are reconstructed in a cylindrical scintillating fiber calorimeter inside the magnet and a lead-glass array downstream. Charged particle identification is achieved by measuring energy loss in the wire chambers and using the flight time of particles between the target and detectors outside the magnet. The signals from all detectors are recorded with flash ADCs and/or pipeline TDCs into memories allowing trigger decisions with a latency of 3.3 $\mu$s. The detector operates routinely at trigger rates of 40 kHz and data rates of 600 megabytes per second. We describe the photon beam, the GlueX detector components, electronics, data-acquisition and monitoring systems, and the performance of the experiment during the first three years of operation., Comment: Accepted by Nuclear Instruments and Methods A, 78 pages, 54 figures

The CABRI experimental pulse reactor, located at the Cadarache nuclear research center, southern France, is devoted to the study of Reactivity Initiated Accidents (RIA). When the thermal-hydraulic conditions representative of a pressurized water nuclear reactor are reached (mostly temperature, pressure and flowrate conditions), a fuel test rod is submitted to a power excursion, triggered by the specific 3He reactivity injection system, in order to simulate a control rod ejection accident. The experiment, managed by IRSN, aims at studying both the fuel and cladding behavior of the test rod placed into the center of the reactor during the power excursion. Several test rods pre-irradiated in pressurized nuclear power plants and with different characteristics (burn up, cladding material, fuel type, Zirconia thickness) are considered for the programs performed in the CABRI reactor. Physical phenomena occurring during the power transient are monitored by various measuring systems designed or operated by IRSN. Each system provides information linked with the different phases of the experiment. Three main measuring systems will be considered in this paper: • The test devices, a sample holder that is also implemented with almost fifty sensors used to monitor the environmental parameters in the test channel such as temperature and pressure, and to control the rod behavior during the test sequence; • The Hodoscope, an online fuel motion measurement system, which aims at analyzing the fuel motion deduced from the detection of fast neutrons emitted by the test rod, with a time step of 1ms during the transient; • The IRIS facility, conceived to perform X-ray radiography and tomography imaging before and after a power transient thanks to a linear electron accelerator, as well as quantitative gamma scanning analyses. During the experimental sequence, different events are recorded. This paper focuses on a cladding failure that occurred during the transient and that can be revealed by the three systems mentioned above. The test device instrumentation allows to determine the timing of the failure and to analyze its consequences in the vicinity of the test rod from a thermal and hydraulic point of view, while the hodoscope measures fuel elongation and relocation during the power excursion. The IRIS facility, then, helps to confirm the failure, its location and its extent. These three systems are complementary and they allow the analysis of the same event from different perspectives. Their combination will ease the interpretation of the events in the next steps for the test results analysis. The study case taken into account in this paper concerns nuclear fuel after three irradiation cycles in a commercial PWR.

Angelis, A. de, et al., The energy range between about 100 keV and 1 GeV is of interest for a vast class of astrophysical topics. In particular, (1) it is the missing ingredient for understanding extreme processes in the multi-messenger era; (2) it allows localizing cosmic-ray interactions with background material and radiation in the Universe, and spotting the reprocessing of these particles; (3) last but not least, gamma-ray emission lines trace the formation of elements in the Galaxy and beyond. In addition, studying the still largely unexplored MeV domain of astronomy would provide for a rich observatory science, including the study of compact objects, solar- and Earth-science, as well as fundamental physics. The technological development of silicon microstrip detectors makes it possible now to detect MeV photons in space with high efficiency and low background. During the last decade, a concept of detector (“ASTROGAM”) has been proposed to fulfil these goals, based on a silicon hodoscope, a 3D position-sensitive calorimeter, and an anticoincidence detector. In this paper we stress the importance of a medium size (M-class) space mission, dubbed “ASTROMEV”, to fulfil these objectives., Open access funding provided by Universita degli Studi di Padova within the CRUI-CARE ` Agreement.