Radiation Signal Research Articles

Cosmology analogues in optical systems

We discuss the possibility of exploiting polariton-exciton physics as an analogue experimental tool to study challenging ideas and existing problems arising in the context of gravity theory and theoretical cosmology. We search for cosmology analogues with specific focus on simulating non-equilibrium dynamics across cosmological phase transitions in laboratory as well as employing optical analogue horizons in Bose-Einstein condensates (BECs) and signatures of white hole radiation to study gravitational and cosmological processes. Our analysis aims to uncover conceptual similarities between condensed matter systems and various phenomena in the Early Universe such as the symmetry breaking of the vacuum energy, spontaneous production of particles, false vacuum and cosmic inflation together with a number of unsolved cosmological problems.

Genetic diversity within and across gametophytic ploidy levels in a Sphagnum cryptic species complex

We deploy Shannon analysis of five ancestrally (ANCE) diagnostic microsatellite loci to explore the patterns of ‘deep’ allelic genetic diversity within the peat moss Sphagnum ×australe Mitt. s.l. cryptic species complex across its Australasian distribution. There is both notable divergence among and considerable allelic overlap within the three allopolyploid lineages of this complex, two gametophytically allodiploid (R1S1 and R2S2) and one gametophytically allotriploid (FR1*S1*). Detailed biogeographic patterns reflect historical differences in genetic isolation and interbreeding. Lineage I (R1S1) occurs in both Australia and New Zealand, while Lineage II (R2S2) and Lineage III (FR1*S1*) are endemic to New Zealand, where Lineage III predominates. Available data suggest that Lineage I arose in Australia, whereas both Lineage II and Lineage III originated in New Zealand. ‘Deep’ allelic diversity provides a pronounced signal of evolutionary radiation within and among the three lineages. We develop a methodology to explore allelic diversity across ploidy levels and elaborate another for scaling additive allele-metric diversity values [0,1], relative to attainable minimal and maximal values, given the sampling frame. We suggest the following taxonomic disposition: gametophytically allodiploid Lineages I and II → S. ×australe; gametophytically allotriploid Lineage III → S. ×antarcticum. Epitypes are designated for both species.

Measurements of the low-energy neutron and gamma ray accompaniment of extensive air showers in the knee region of primary cosmic ray spectrum

Purposeful investigation of radiation fluxes strongly delayed in relation to the main particles front of extensive air shower (EAS) was undertaken at the Tien Shan Mountain Cosmic Ray Station. It was found that the passage of the EAS can be accompanied by the delayed thermal neutrons and by the soft $(30-50)$ keV gamma rays, mostly concentrated within a region of about $(5-10)$ m around shower axis, where the integral radiation fluence can vary in the limits of $(10^{-4}-1)$ cm$^{-2}$ for neutrons, and of $(0.1-1000)$ cm$^{-2}$ for gamma rays. The dependence of signal multiplicity on the shower size $N_e$ has a power shape both for the neutron and gamma ray components, with a sharp increase of its power index around the value of $N_e\approx 10^6$, which corresponds to the position of the $3\cdot10^{15}$ eV knee in the primary cosmic ray spectrum. Total duration of detectable radiation signal after the EAS passage can be of some tens of milliseconds in the case of neutron component, and up to a few whole seconds for gamma rays. The delayed accompaniment of low-energy radiation particles can be an effective probe to study the interaction of the hadronic component of EAS.

Часові параметри оптимальної реєстрації емісійного спектра при використанні мілісекундних лазерних імпульсів

Subject and Purpose. Emission spectra of copper-silver alloys are examined for various recording durations. The radiation coming to the photodetector of the spectrometer consists of the reflected laser radiation and the line spectra of vapors formed by the test substance and the heated material in condensed phase. As the spectrum recording time increases, the background component builds up substantially. The purpose of the work is to study the interaction conditions of millisecond laser pulses with the metals and determine recording time parameters of the optical radiation signal in an effort to achieve an optimal recording of the emission spectrum in the range 400…800 nm Methods and Methodology. The main problem with emission spectrum recording is a persistent thermal component. The laser pulse shape for the optimal recording of the emission spectrum is theoretically calculated. The purity of the emission spectrum depends on its recording duration. The matter of persistent thermal component minimization in laser emission analysis implies the optimal shaping of the laser pulse and its maintenance during the operation. Empirical guidelines exist that the optimal time of the emission spectrum recording is 1...3 ms at a laser pulse duration of 5 ms. Results. It has been found that the main factors affecting the intensity ratio of the continuous and line spectra are thermophysical properties of the metal and a laser pulse shape, especially the value of its trailing edge steepness. Lasers with quasi-optimal pulse shape enable us to increase a maximum frequency of optimal emission-spectrum recording in laser emission analysis. For a 3 ms duration and a 10 J energy of the pulse, the maximum laser frequency at which the laser emission analysis is still possible can be 70...75 Hz. Conclusion. The process of laser emission analysis optimization consists in optimal laser pulse shaping and its maintenance during the operation.

Analysis of geoacoustic emission and electromagnetic radiation signals accompanying earthquake with magnitude Mw = 7.5

The paper is devoted to the analysis of frequency spectra and pulse waveform variety of the geoacoustic and electromagnetic signals recorded on Kamchatka Peninsula at “Karymshina” site during seismically calm and active periods. Signal pre-processing includes pulse detection and their waveforms reconstruction. A frequency spectrum is analyzed using the Adaptive Matching Pursuit algorithm. To study a variety of waveforms, each pulse is encoded by a special descriptive matrix. Then pulse classification based on similarity of the descriptive matrices is performed. Thus, a signal alphabet is formed. The authors analyzed the geophysical signals recorded before, during and after the earthquake with the magnitude Mw = 7.5 dated March 25, 2020. The obtained estimates of frequency spectra and signal alphabets are compared with the analysis results of signal recoded during the seismically calm period of March 22, 2020.

Numerical Investigation on Flow and Radiation Characteristics of Solid Rocket Motor Plume Near the Ground

Abstract Solid rocket motor stabilizes combustion by adding aluminum powder, and to increase the force of the thrust. The combustion product of the engine is accelerated by the nozzle to form a high temperature and pressure two phase plume. A strong infrared radiation signal is produced. This paper is aimed at a model solid engine. Euler Lagrange method is used to describe the interaction between gas and solid particles, the detailed chemical reaction mechanism is used to calculate the afterburning effect in the plume. The radiative parameters of gases by line by line integration and particles are solved by the Mie theory. The particle scattering approximation method and light of sight method are used to calculate the radiation transmission, and the flow and radiation characteristics of the two phase plume of the solid engine are calculated and analyzed.

Magnetic field propagation model of low frequency/very low communication based on mechanical antenna of electret

<sec>Because of its stable propagation characteristics and small attenuation in the medium, low-frequency (LF) electromagnetic wave can penetrate into the sea and underground with small loss. Although its transmission bandwidth is narrow, which limits its application range, it has irreplaceable wide applications in long-distance navigation, communication and frequency release, especially in underwater communication. Therefore, the study of low frequency/very low frequency (LF/VLF) propagation is of great theoretical and military value. In the LF/VLF communication systems, the transmitting antenna is an extremely important part, and its performance has an important influence on the whole system. However, the wavelength of the LF electromagnetic wave is very long. In order to obtain the ideal radiation effect, the traditional method needs a huge transmitting antenna system, which is too large in size and power consumption. Therefore, it will be a disruptive innovation in the field to realize a technology that can significantly reduce the size the existing LF/VLF information network communication system. </sec><sec>In view of this, in this paper we propose a kind of LF/VLF signal transmitting antenna in which an excitation device is used to drive the polarization charge of the electret to move mechanically. By accelerating the charge to form a conductive alternating electromagnetic field which can generate and radiate electromagnetic wave, under the excitation of the wave source, it carries the energy and information in the form of energy flow and propagates in a certain medium. Then, through using the magnetic field receiving system to measure the magnetic field vector in the electromagnetic wave, the effective LF/VLF signal can be obtained, thus achieving the high electromagnetic wave effective radiation which overturns the restriction that the antenna size needs to be comparable to the wave length of the radiation signal in the traditional LF navigation communication system. At the same time, an analytical model of magnetic field propagation is established based on this structure, and the influence of antenna size, shape and other relevant parameters on the performance of antenna communication are studied as well. In order to reduce the loss of accuracy and improve the calculation speed, it is necessary to choose the correct analytical model and the appropriate parameters of magnetic field generated by the mechanical antenna according to the actual situation. The research work is of great significance for designing and optimizing mechanical antennas.</sec>

Evaluation of LJ1-01 Nighttime Light Imagery for Estimating Monthly PM2.5 Concentration: A Comparison With NPP-VIIRS Nighttime Light Data

Air quality degradations caused by fine particulate matter (PM2.5) can lead to various health problems, and accurate PM2.5 data are critical for managing the environment and ensuring public health. Radiation signals collected by nighttime light (NTL) remote sensing satellites are influenced by PM2.5 concentrations, and thus, incorporating NTL imagery in statistical models has been widely used to predict PM2.5 concentrations. However, scarce work has been carried out with new-generation NTL data from the LJ1-01 satellite, which has a fine spatial resolution and wide measurement range. In this study, we integrated satellite observation data and meteorological data to construct five models based on the geographically weighted regression to validate the feasibility of LJ1-01/NPP-VIIRS in Moderate Resolution Imaging Spectroradiometer AOD-based PM2.5 prediction in the Beijing–Tianjin–Hebei region. The models were validated by the cross-validation method. The results showed that the addition of NTL information could improve the performance of the PM2.5 prediction model. The seasonal R 2 with NTL in AOD-PM2.5 model have improved by 5.07%, 4.50%, 2.95%, and 2.56% in model fitting and 1.20%, 1.75%, 2.20%, and 4.41% in cross-validation. Furthermore, the LJ1-01 NTL data revealed additional details and improved the prediction accuracy, compared with the NPP-VIIRS in AOD-PM2.5 model, the seasonal R 2 with LJ1-01 in AOD-PM2.5 model increased by 1.16%, 1.79%, 0.76%, and 1.15% in model fitting and 1.04%, 0.85%, 0.78%, 1.37% in cross-validation. Thus, our findings indicate that LJ1-01 and NTL data have the potential for predicting PM2.5 and that they could constitute a useful supplemental data source for estimating ground-level PM2.5 distributions.

A Method for Blind Source Separation of Multichannel Electromagnetic Radiation in the Field

Considering the multichannel instability, spectral overlap and strong interference of electromagnetic radiation signals in the integrated electric propulsion systems of ships, a new method is proposed which combines multivariate empirical mode decomposition (MEMD) with independent component analysis (ICA) for synchronous blind source separation of multichannel electromagnetic radiation in the field. In order to construct virtual channels, noise-aided MEMD is first applied to decompose multichannel data in this approach. Then the comprehensive screening algorithm is used to filter the intrinsic mode functions (IMFs) produced by the decomposition procedure. Finally, the new multivariate input signal is analyzed after screening using ICA to obtain the original electromagnetic radiation source signal. This method is able to effectively addresses several limitations of EMD including the mode mixing problem, its inability to handle multichannel data, as well as the indeterminacy problem in ICA. The efficacy of the MEMD-ICA algorithm was evaluated using simulated signals and real world data from a cruise ship, and comparing ensemble empirical mode decomposition-ICA(EEMD-ICA).

Quasi-two-dimensional van der Waals semiconducting magnet CrSiTe<sub>3</sub> studied by using THz spectroscopy

Quasi-two-dimensional van der Waals ferromagnetic semiconductor CrSiTe<sub>3</sub> with wide potential applications in optoelectronics and nanospintronics has aroused the immense interest of researchers due to the coexistence of intrinsic magnetism and semiconductivity. By combining untrafast femtosecond laser and terahertz spectroscopy, including terahertz time-domain spectroscopy, optical pump-terahertz probe spectroscopy and terahertz emission spectroscopy, we carry out systematic investigation into the van der Waals ferromagnetic semiconductor CrSiTe<sub>3</sub> crystal. The experimental results indicate that the conductivity of the sample is robust against the temperature change and isotropic terahertz transmission in the <i>ab</i>-plane. Moreover, it is also observed that the photocarriers induced by 800 nm optical pump exhibit a relaxation in the biexponential form and the complex photoconductivity can be well reproduced by the Drude-Smith model. The main relaxation channel of photocarriers is the recombination of electron-hole pairs. With femtosecond pulse illuminating the surface of sample, a strong terahertz radiation signal with a broad band of 0–2 THz is observed. The present study provides the responses of CrSiTe<sub>3</sub> to optical and terahertz frequency and offers crucial information for the future design of CrSiTe<sub>3</sub>-based electronic and optoelectronic devices.

MATHEMATICAL MODEL OF THE ESTIMATION OF THE EFFICIENCY OF THE CONTROL OF RADIO ELECTRONIC COUNTERACTION OF THE AIRPORT STATION OF ACTIVE CONTEMPORARY INTERFERENCES IN THE CONDITIONS OF CREATING A POLARIZATION INTERFACE ON A FIXED PLANE OF IT

In the article, based on the analysis of the use of modern individual on-board electronics and electronic search and guidance systems, it is concluded that one of the promising directions for their further development is the search for methods of not only protection from the means of radio-electronic suppression, but also an active counteraction to these means, the so-called counter-radio electronic counteraction One of the most effective obstacles that can be created by radar detection systems by stations is the active barrier of individual enemy protection - this is a polarizing obstacle, so the issue of reducing the effectiveness of the polarizing effect on the system of automatic support for the direction of the on-board radar weapon control system is quite relevant today. In order to counteract the station's active interference in the conditions of its creation of a polarization obstacle, it is proposed to change the plane of polarization on the receiving side. As a result, a useful signal will be taken in polarization, which does not coincide with the polarization plane of the radiation signal. Failure to match polarization when receiving a reflected signal will not significantly affect the power of a useful signal. In order to implement the proposed method in the article, a mathematical model for evaluating the effectiveness of the counter-radio-electronic counteraction of the on-board station was proposed to obstruct the enemy's individual protection in the conditions of its creation of a polarization obstacle on a fixed plane of polarization, as well as features of the practical realization of such counteraction during air combat and restrictions on its creation. The mathematical model of the evaluation of the effectiveness of the counter-electronic counteraction to the aircraft station's active barriers in the conditions of its creation of a polarization obstacle on a fixed plane of polarization is developed, it will allow to formulate practical recommendations regarding the application of the developed method at different stages of air combat. KELP management in different ways, on the one hand, slightly reduces the effectiveness of the on-board management of weapons at different stages of flight, but on the other hand, the effectiveness of the airborne equipment of the airborne ejection of the enemy significantly decreases, which will increase the effectiveness of the use of weapons and the likelihood of damage to the enemy aircraft using the means of destruction, which today have a significant cost.

The effect of temperature on g-effective values of soda-lime samples irradiated at different doses

Electron spin resonance (ESR) dosimetry aims to investigate different materials for the purpose of reconstruction of the dose absorbed by the victims of radiological and nuclear accidents. The soda-lime glass is very popular as retrospective dosimeter due its availability. In the dose range below 2 Gy soda-lime glass ESR signal of radiation induced radicals overlaps with the background ESR signal and limit the dose reconstruction. Recently it was shown that the behavior of g-effective value is useful tool for dose reconstruction for triage application. Therefore, in this research, effects of temperature on the time stability of the g-effective values, the temperature dependence of the g-effective values and on the previously proposed g-effective approach were studied. The time stability was tested for the temperatures 200 K and 300 K. The g-effective values remained unchanged at both sample temperatures within 2 months after irradiation.The temperature dependence of the g-effective values was investigated in the range from 180 K to 300 K for the samples irradiated with doses 0.3, 0.5, 0.7, 1, 2 and 5 Gy. The results show that temperature of the sample is not influencing the g-effective value. Furthermore, all of the samples exhibit previously proven approach for the g-effective value exponential dependence on the dose. The temperature dependence of the approach was investigated within temperature range from 200 K to 300 K and the results are consistent with previous research. This proves that g – effective value is stable parameter with temperature and within 2 months after irradiation and therefore useful for application in retrospective dosimetry.

Characteristics of electromagnetic radiation signal of coal and rock under uniaxial compression and its field application

Rockburst is a serious threat to the safety and efficiency of coal-mine production in China. Accurate monitoring and prediction of rockburst is an ongoing challenge in coal mining. Electromagnetic radiation (EMR) technology is a real-time and non-contact prediction method for changes in the mechanical parameters of coal or rock. In this paper, uniaxial compression testing of coal and rock samples was carried out, EMR data were collected and analysed from deformation to failure. The rescaled range (R/S) analysis method was applied to study the Hurst index of the EMR signals during the uniaxial compression test. The results showed that the higher the degree of deformation and failure, the larger the Hurst index. On the basis of the experimental and theoretical results, the Hurst index of the EMR signal during the ‘8.11’ rockburst in the Yuejin coal mine was analysed. The results showed that the Hurst index was low before the rockburst, and increased to 0.9 in the pre-rupture stage, then decreased 1–2 days before the rockburst. This suggests a correlation between EMR and the conditions leading to a rockburst event. Therefore, further study on the characteristics of EMR can contribute to development of early-warning technology for rockburst.

Thermal microelectromechanical sensor construction

The problem of constructing a thermal sensor based on the technology of microelectromechanical systems is solved by structural and circuit integration of capacitance-dependent and thermomechanical parts. For this, the use of a MOS transistor (capacitance-dependent part) with a gate in the form of a bimorph membrane (thermomechanical part), which performs cyclic oscillations under the influence of heating from a sensitive element and subsequent cooling, is proposed. The novelty of the proposed sensor is the provision of a frequency-dependent output signal without the use of additional generator circuits. This makes it easier to combine the sensor with digital signal processing systems and reduce the influence of transmission lines on measurement accuracy. Also, the advantages of the sensor include reduced overall dimensions, which is achieved due to the vertical integration of its elements.Model studies of the sensor are carried out and on their basis circuit and software-hardware solutions for determining the temperature of the sensitive element are proposed. It is shown that the use of logarithmic dependence to approximate the influence of the temperature of the sensitive element on the output pulse frequency of the sensor minimizes the measurement error to 3.08 %. The composition of the information and measurement system, which contains a thermal sensor, a sensor signal pre-processing circuit and measurement processing unit using the Atmega328 microcontroller on the platform of the unified ArduinoUno module, is determined. It is shown that the total error of temperature determination in the developed system does not exceed 4.18 % in the temperature range of the sensor element from 20 °C to 47 °C.The program code for the microcontroller part of the information and measurement system is developed, which occupies 12 % of the program memory and 4.9 % of the dynamic memory of the unified module.The proposed thermal microelectromechanical sensor can be used for contact measurement of the temperature of gaseous and liquid media, recording of optical radiation and microwave signals

Generation of a Transcriptional Radiation Exposure Signature in Human Blood Using Long-Read Nanopore Sequencing.

In the event of a large-scale event leading to acute ionizing radiation exposure, high-throughput methods would be required to assess individual dose estimates for triage purposes. Blood-based gene expression is a broad source of biomarkers of radiation exposure which have great potential for providing rapid dose estimates for a large population. Time is a crucial component in radiological emergencies and the shipment of blood samples to relevant laboratories presents a concern. In this study, we performed nanopore sequencing analysis to determine if the technology can be used to detect radiation-inducible genes in human peripheral blood mononuclear cells (PBMCs). The technology offers not only long-read sequencing but also a portable device which can overcome issues involving sample shipment, and provide faster results. For this goal, blood from nine healthy volunteers was 2 Gy ex vivo X irradiated. After PBMC isolation, irradiated samples were incubated along with the controls for 24 h at 37°C. RNA was extracted, poly(A)+ enriched and reverse-transcribed before sequencing. The data generated was analyzed using a Snakemake pipeline modified to handle paired samples. The sequencing analysis identified a radiation signature consisting of 46 differentially expressed genes (DEGs) which included 41 protein-coding genes, a long non-coding RNA and four pseudogenes, five of which have been identified as radiation-responsive transcripts for the first time. The genes in which transcriptional expression is most significantly modified after radiation exposure were APOBEC3H and FDXR, presenting a 25- and 28-fold change on average, respectively. These levels of transcriptional response were comparable to results we obtained by quantitative polymerase chain reaction (qPCR) analysis. In vivo exposure analyses showed a transcriptional radioresponse at 24 h postirradiation for both genes together with a strong dose-dependent response in blood irradiated ex vivo. Finally, extrapolating from the data we obtained, the minimum sequencing time required to detect an irradiated sample using APOBEC3H transcripts would be less than 3 min for a total of 50,000 reads. Future improvements, in sample processing and bioinformatic pipeline for specific radiation-responsive transcript identification, will allow the provision of a portable, rapid, real-time biodosimetry platform based on this new sequencing technology. In summary, our data show that nanopore sequencing can identify radiation-responsive genes and can also be used for identification of new transcripts.

Above-cloud aerosol radiative effects based on ORACLES 2016 and ORACLES 2017 aircraft experiments

Abstract. Determining the direct aerosol radiative effect (DARE) of absorbing aerosols above clouds from satellite observations alone is a challenging task, in part because the radiative signal of the aerosol layer is not easily untangled from that of the clouds below. In this study, we use aircraft measurements from the NASA ObseRvations of CLouds above Aerosols and their intEractionS (ORACLES) project in the southeastern Atlantic to derive it with as few assumptions as possible. This is accomplished by using spectral irradiance measurements (Solar Spectral Flux Radiometer, SSFR) and aerosol optical depth (AOD) retrievals (Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research, 4STAR) during vertical profiles (spirals) that minimize the albedo variability of the underlying cloud field – thus isolating aerosol radiative effects from those of the cloud field below. For two representative cases, we retrieve spectral aerosol single scattering albedo (SSA) and the asymmetry parameter (g) from these profile measurements and calculate DARE given the albedo range measured by SSFR on horizontal legs above clouds. For mid-visible wavelengths, we find SSA values from 0.80 to 0.85 and a significant spectral dependence of g. As the cloud albedo increases, the aerosol increasingly warms the column. The transition from a cooling to a warming top-of-aerosol radiative effect occurs at an albedo value (critical albedo) just above 0.2 in the mid-visible wavelength range. In a companion paper, we use the techniques introduced here to generalize our findings to all 2016 and 2017 measurements and parameterize aerosol radiative effects.

Effect of water on the time-frequency characteristics of electromagnetic radiation during sandstone deformation and fracturing

In order to study the effect of water on the electromagnetic radiation (EMR) signals released during rock deformation and fracturing, uniaxial compression experiments were performed on sandstone samples with different water contents. During the experiments, the EMR signals were acquired. Furthermore, the time-frequency characteristics of the signals were analyzed, and their generation mechanism and the effect of water were discussed in depth. The results show that the EMR energy released decreases gradually with the increase of water content, and the EMR energy and water content can be linked by a binomial equation. For sandstone with higher water content, the precursor characteristics of EMR released in the fracturing process are more obvious. With the increase of water content, the proportion of signals in the low frequency band grows gradually, while that of signals in high frequency band falls gradually. Water reduces the macroscopic mechanical strength and fracture mechanical characteristics of sandstone, which weakens the EMR signals produced by piezoelectric effect and charge separation. Besides, with respect to the microscopic fracturing mode, the sandstone with higher water content is more likely to undergo inter-granular fracturing, which may be an important microscopic reason for the weakening of EMR of water-bearing sandstone. An EMR-based damage evolution model of water-bearing sandstone was preliminarily established, and the model helps to calculate the stress state of water-bearing rock.

A study of flames with millimeter-wave radiation

It is a valuable issue to explore whether a flame can radiate microwaves, in spite of the electric field formed in the flame. Presented herein is an experimental study on a series of flames with millimeter-wave radiation in the combustion of pyrotechnic films. The pyrotechnic films were composed of ultra-fine red phosphorus (P), sodium nitrate (NaNO3), Polyvinyl Alcohol (PVA) and some additives such as chopped carbon fibers (CFs) and aluminized glass fibers (GFs). The combustion temperatures and millimeter-wave radiation signals of the flames were measured, the millimeter-wave emissivity and spectral radiant exitance were calculated to describe the millimeter-wave radiation intensity. The results demonstrate that the flame of the pyrotechnic films based on P/NaNO3/CFs can radiate millimeter waves, and different materials and their proportion have a great effect on the millimeter-wave radiation intensity.

Comments on the paper “Two independent real-time precursors of the 7.8 M earthquake in Ecuador based on radioactive and geodetic processes – Powerful tools for an early warning system” by Toulkeridis et al. (2019)

In the paper entitled “Two independent real-time precursors of the 7.8 M earthquake in Ecuador based on radioactive and geodetic processes – Powerful tools for an early warning system”, Toulkeridis et al. (2019) claim that they found radiation and GPS signal anomalies before the April 16th 2016 Pedernales earthquake (Ecuador) and that their findings can be used to forecast earthquakes in the medium and short term in active continental margins. Using an extended data set that overlaps Toulkeridis et al. (2019) study period, we find: (1) the success rate of predicting earthquakes using radiation anomalies is 2.5 %; (2) radiation anomalies, including the one recorded during the hours before the M 7.8 earthquake, temporally correlate with local rainfall; (3) Toulkeridis et al. (2019) GPS results are physically unrealistic and inconsistent with previously published GPS and InSAR analysis; (4) there is no anomaly in the GPS time series before the earthquake. Therefore, Toulkeridis et al. (2019) results are not reliable evidence of precursors to the M 7.8 earthquake in 2016 in Ecuador, and their proposed method cannot be used to forecast earthquakes.

Vintage electronics for trusted radiation measurements and verified dismantlement of nuclear weapons.

Information barriers are trusted measurement systems to confirm the authenticity of nuclear warheads based on their radiation signatures. Traditional inspection systems rely on complex electronics both for data acquisition and processing. Several research efforts have produced prototype systems, but it has proven difficult to demonstrate that hidden switches and side channels do not exist. After almost thirty years of research and development, no viable and widely accepted system has emerged. We pursue a fundamentally different approach: Our prototype of an inspection system uses vintage hardware built around a 6502 processor. The processor uses 8-micron technology and has only about 4,200 transistors. Vintage electronics may have a number of important advantages for applications where two parties need to simultaneously establish trust in the hardware used. CPUs designed in the distant past, at a time when their use for sensitive measurements was never envisioned, drastically reduce concerns that the other party implemented backdoors or hidden switches on the hardware level. We demonstrate the performance of a prototype system using an Apple IIe and a custom-made open-source data-processing board connected to a standard sodium-iodide radiation detector for low-resolution gamma spectroscopy. Data processing and analysis is exclusively done on the Apple IIe hardware. We show that subtle differences in radiation signatures can be detected in 2–3 minutes based on the result of a simple chi-squared test. Vintage electronics may therefore offer a new path toward fieldable, trusted information barriers.