Nuclear Pulse Research Articles

Inertial Confinement Fusion Propulsion for the Massive Ra World Ship Model – Part 2

A strategy for sending humans around other stars will be to acquire the ability to construct large World Ships which are of order ~1011-1012 tons in mass, ~100 km in length and host large populations of millions of people over many generations of lifetime. This paper presents such a concept but driven by inertial confinement fusion engines utilising very large pellets of order 230 g in mass augmented with 4.85 kg/pellet of expellant propellant for increased mass flow rate and thrust generation. A mission architecture is constructed for a 1 million population carrying capacity growing to 10 million, based on an original 1984 published model which achieved a cruise speed of 1,500 km/s or 0.5% for a 1,000 year trip time. Calculations show that propulsion of such a vast construction will require hundreds of engines operating in parallel thrust mode and at moderately high pulse frequency for an elongated burn time of order half a century. The purpose of this study was to examine whether it was possible to drive an interstellar world ship using ICF engines using similar assumptions to a 1984 study for a Mk2A design. The conclusion of this study is that although an architecture does appear to be possible, there are practical reasons why it may be better to pursue alternative propulsion methods for this specific application such as via external nuclear pulse propulsion as adopted for the original studies. This paper is a follow-up to an earlier one which discussed some of the assumptions of the study. Keywords: World Ships, Interstellar Studies, Fusion Propulsion

FPGA implementation and measurement of cusp-flattop hybrid filter shaping method for nuclear instruments

In the field of nuclear technology applications, digital multi-channel pulse amplitude analysis technology plays an indispensable role in information acquisition due to its high precision and sensitivity. However, the challenge of pulse pileup can compromise the accuracy of measurement results in this technology. While conventional filter shaping and pulse pileup processing methods can extract nuclear pulse feature information under mild pileup conditions, severe pileup can notably degrade spectral counting rate and resolution. This paper introduces a designed two-channel pulse pileup rejection method, termed the cusp-flattop hybrid filter forming algorithm, leveraging the unique features of cusp, such as high forming speed and minimal interference from pulse pileup. The two channels simultaneously process the collected signals and utilize their differences for data filtering and rejection. This approach enhances information content, improves data processing quality, and boosts the signal-to-noise ratio. Compared to three methods—three trapezoidal filter shaping algorithms, the triangle trapezoidal pulse shaping algorithm, and the pulse width discrimination algorithm—our proposed method refines the shaping threshold of pulse pileup rejection. It accurately distinguishes and extracts effective pulse amplitudes even under severe pileup conditions, generating energy spectrum results while accounting for counting rate and resolution. Building on this, we construct a digital multichannel pulse amplitude analysis system based on FPGA (Field Programmable Gate Array) and use a national standard alloy sample, YSBS41346, for testing. The system can generate energy spectrum correctly, consistent with the actual sample content. We evaluate the system's performance by comparing the peak counting rate and resolution of the energy spectrum generated by the cusp-flattop hybrid filter forming algorithm and the trapezoidal forming algorithm. A high peak counting rate represents the maximum nuclear pulse data captured by the system, while low resolution indicates more valid data after pileup rejection. Through testing, the peak counting rate reaches 12843cps, with a resolution of 6.68%, marking a significant improvement over the trapezoidal pulse forming algorithm. The system demonstrates satisfactory performance and operational effectiveness, aligning with the design objectives and presenting innovative and practical applications.

Internal Nuclear Propulsion System for Future Space Applications

Internal nuclear pulse propulsion (INPP) represents a novel approach to space propulsion, where controlled nuclear detonations occur within the spacecraft itself, offering potential advantages in safety and propulsion control compared to conventional external detonation designs like Project Orion. INPP relies on the same fundamental principles of nuclear pulse propulsion, utilizing the momentum generated by nuclear explosions to propel the spacecraft forward. Proposed INPP designs involve strategically placing small nuclear devices within the spacecraft's structure, detonating them in sequence to produce controlled impulses for propulsion. However, significant engineering challenges, such as radiation shielding, precise detonation control, and safety considerations, must be addressed to realize the full potential of INPP. Despite these hurdles, ongoing research and development efforts aim to harness the transformative capabilities of INPP, promising to revolutionize space exploration by enabling efficient and rapid interstellar travel while ensuring the safety of spacecraft and crew.

Study on gamma spectrum measurement of high-dose-rate radiation

Currently, spectrometers are almost used for spectrum measuring of low-dose-rate radiation. Therefore, the sensitive volume of the spectrometer detector is usually big, and the width of the nuclear pulse is often wide. The pulse throughput of the spectrometer does not have to be very high. However, if a nuclear accident or a nuclear burst occurs, the dose rate will be high. When we measure the spectrum of the radiation, pulses output from the spectrometer detector will pile up seriously. The current spectrometer cannot meet the needs of high-dose-rate radiation energy spectrum measurement. To solve the problem of spectrum measuring of high-dose-rate radiation, in this paper, a solution of measuring the gamma spectrum of high-dose-rate radiation is put forward, and many measures are taken, such as lessening the detector volume, detector shielding, narrowing down the nuclear pulse width, pulse anti-pileup, and increasing the pulse throughput of the multi-channel analyzer through FPGA parallel processing. Analysis design and experiment show that the gamma spectrum of high-dose-rate radiation can be measured through these measures.

Pulse Signal Generator for Simulated Gamma-ray Spectrometer Detection

This paper introduces an integrated nuclear pulse generator aimed at simulating authentic radiation detection signals, allowing for the convenient calibration and testing of nuclear instruments without the need for radioactive sources. An innovative method is adopted, generating energy spectrum distributions via Monte Carlo simulation and deriving nuclear pulse waveforms using difference equations. This approach enables real-time computation of particle transport processes on a hardware platform, and generates pulse sequences that closely resemble the statistical characteristics of actual nuclear events. Compared to traditional nuclear signal generators, this new type of generator significantly enhances the flexibility and real-time capabilities of the equipment, as it no longer relies on pre-stored empirical data or simulation software to generate energy spectrum data. As a case for gamma-ray spectrometer detection, the signal waveforms and energy spectrum distributions produced closely match those obtained using a NaI scintillation detector in a lead chamber to detect a Cs-137 source.

Review of Research on Nuclear Signal Pulse Shaping

Pulse shaping can greatly improve the signal-to-noise ratio and has been widely used in nuclear signal processing. This paper gives a brief overview of the current research status of nuclear signal pulse shaping at home and abroad. It describes in detail the three traditional pulse shaping methods of quasi-Gaussian shaping, triangular shaping and trapezoidal shaping, and discusses the nuclear pulse signal shaping that has appeared in recent years. And a brief introduction to the nuclear pulse signal shaping methods that have emerged in recent years is also given.

Design and implementation of a virtual nuclear pulse signal generator

This paper presents a virtual nuclear pulse signal generator. The pulse generator can be used in specific scenarios such as calibration and maintenance of nuclear detection systems, validation of nuclear signal processing algorithms, and nuclear physics teaching experiments, as a substitute for real radioactive sources and detectors to generate nuclear pulse signals. This helps to avoid exposing experimental personnel to radiation hazards. The pulse generator is capable of generating specific nuclear pulse signals according to experimental requirements, and these signals has the same physical characteristics as real nuclear pulse signals, including amplitude distribution, time and amplitude randomness. In the pulse generator, we conducted theoretical analysis of the radioactive source and detector, and established a model library for both, to obtain crucial parameters of the nuclear pulse signals. The pulse generator is built on a hardware framework with field-programmable gate array (FPGA) as the core, utilizing these key parameters to generate signals with realistic physical characteristics of nuclear pulse signals, including amplitude and time characteristics. The counting rate of the output nuclear pulse signals can be adjusted by configuring the hardware parameters of the pulse generator.

Impact Initiated Nuclear Pulse Propulsion and Applications

A new iteration of nuclear pulse propulsion (NPP) is investigated in which propulsive nuclear explosions are initiated via hypervelocity impacts. Working entirely without a fission first stage and requiring precise planning of orbits often years in advance, this new iteration, being intrinsically difficult to weaponise, is suited only to peaceful and commercial purposes and so sidesteps the political issues regarding weapons proliferation that have so far prevented use of NPP as originally envisioned (in the form of Project Orion) despite high potential utility and technological maturity demonstrated. Use of Jovian gravity assist/Oberth effect burn to invert a Hohmann transfer orbit into a retrograde ellipse is investigated and suggests that collision velocities with a waiting spacecraft propulsion system could be attained upwards of 70 km/s. Potential schemes for fusion chain reaction initiation are suggested: 1) Inversion of impactor plate by collision with conical annulus into a collapsing cylindrical tamper, 2) Plasma Z-pinch powered by induction of fast moving permanent magnet through a conducting coil, 3) Impact induced x-ray flash powering spherical tamper collapse by ablation as in conventional Teller-Ulam systems, as well as how these may be used in combination. Further avenues for research are suggested. Keywords: Nuclear Pulse Propulsion, Project Orion, Hypervelocity Impact, Spaceflight

Non-iterative pulse tail extrapolation algorithms for correcting nuclear pulse pile-up

Radiation detection systems working at high count rates suffer from the overlapping of their output electric pulses, known as pulse pile-up phenomenon, resulting in spectrum distortion and degradation of the energy resolution. Pulse tail extrapolation is a pile-up correction method which tries to restore the shifted baseline of a piled-up pulse by extrapolating the overlapped part of its preceding pulse. This needs a mathematical model which is almost always nonlinear, fitted usually by a nonlinear least squares (NLS) technique. NLS is an iterative, potentially time-consuming method.The main idea of the present study is to replace the NLS technique by an integration-based non-iterative method (NIM) for pulse tail extrapolation by an exponential model. The idea of linear extrapolation, as another non-iterative method, is also investigated. Analysis of experimental data of a NaI(Tl) radiation detector shows that the proposed non-iterative method is able to provide a corrected spectrum quite similar with the NLS method, with a dramatically reduced computation time and complexity of the algorithm. The linear extrapolation approach suffers from a poor energy resolution and throughput rate in comparison with NIM and NLS techniques, but provides the shortest computation time.

Implementation of FPGA based real-time digital DAQ for high resolution, and high count rate nuclear spectroscopy application

This paper investigates a digital system for real-time nuclear data (pulse) analysis based on a field programmable gate array and a computer-based data acquisition software for high count rate and high-resolution spectroscopy applications. A novel FPGA-based design is proposed with enhanced universality for real-time energy spectroscopy applications encompassing gamma and charged particles in noisy environments. This design implements an adaptive digital pre-filter for noise reduction without distorting the preamplifier pulse shape for improvement in energy resolution. This adaptive approach can be used for a wide range of input pulses with varying rise and fall times without deteriorating the signal-to-noise ratio. The design incorporates a digital trapezoidal filter with a triggerless peak detection algorithm for improvement in energy resolution. A high-speed dual clock first-in-first-out memory is implemented for handling high data rates. The real-time analysis of the FPGA internal signals and nuclear spectroscopy experiments with high count rate have been carried out with random nuclear pulses using an emulator. The results have been compared with conventional VERSA-Module Euro data acquisition system and CR_RC based digital pulse processing approaches.

Real-time environmental radiation monitoring based on locally developed low-cost device and unmanned aerial vehicle

In this study, a low-cost local device based on an Unmanned Aerial Vehicle (UAV) for real-time environmental radiation monitoring is proposed. The device consists of a Geiger-Müller ZP 1200 counter for gamma radiation detection and an appropriate electronic circuit for processing and shaping the detected pulses. The Geiger-Müller detector used is low-cost, insensitive to environmental temperature variations, and can be operated continuously over a long period. Two different methods were performed to calibrate the designed device, namely the use of a programmable nuclear pulse generator for electronic calibration and a Cs-137 gamma-ray calibration source. A long flight time UAV is developed locally with suitable characteristics and adapted to carry the radiation detection device. The designed UAV mainly consists of a multi-flight controller having an intelligent switching system associated with a GPS Module for accurate position-keeping and four heavy lift motors. The use of UAVs has the advantage that it allows measurements to be taken over large areas, even those that are difficult to access, and avoids exposing people to radiation. The flight measurement tests were carried out in the urban area of Yaoundé-Cameroon, at an altitude of 15 to 100 meters with a sweeping speed of about 20 km/h for 36 days from January 01, 2023, to February 06, 2023. The tests showed that the concentrations collected varied between 0.00697 μSv/h and 0.8706 μSv/h, of which 85.71% of data have a concentration below the threshold (0.3 μSv/h) and 14.29% above this threshold. These tests confirm that the developed radiation detection system works properly and is suitable for environmental radiation protection and nuclear safety activities.

Novel radionuclides identification method based on Hilbert–Huang Transform and Convolutional Neural Network with gamma-ray pulse signal

Traditional radionuclide identification algorithms are based on gamma-ray spectrum analysis. A novel radionuclide identification method was proposed in this work and it was based on the combined use of the Hilbert–Huang Transform and a Convolutional Neural Network (HHT-CNN) and taken as input data gamma-ray pulses, instead of an entire gamma-ray spectrum. Firstly, HHT was used to analyze the nuclear pulse signal in frequency domain, and then the frequency in the instantaneous-frequency-edge spectrum was divided into multiple intervals, and the accumulation of amplitude in each interval was taken as the characteristic of the nuclear pulse signal. After constructing the data set with signal features, the one-dimensional Convolutional Neural Network (1D-CNN) model was established and trained to complete the nuclide recognition. In the simulated experiments, the model was tested by the nuclear pulse signals of 137Cs, 60Co, 152Eu, 133Ba, 40K, 60Co+137Cs, 60Co+152Eu and 137Cs+152Eu, which were simulated with the Geant4 toolkit and pulse signal simulator DT5800D (produced by CAEN Technologies Inc.). At the same time, the influence of pulse number and noise on the model recognition results was discussed. Finally, the model was applied to the actual experimental data to verify the model’s feasibility further. The results show that the proposed method can quickly and accurately identify radioactive nuclides. The study provides a new solution for radionuclides identification.

Gaussian shaper for nuclear pulses based on multilevel cascade convolution

Gaussian shaper for nuclear pulses based on multilevel cascade convolution

Trapezoidal pile-up nuclear pulse parameter identification method based on deep learning transformer model

Pile-up between adjacent nuclear pulses is unavoidable in the actual detection process. Some scholars have tried to apply deep learning techniques to identify pile-up nuclear pulse parameters. However, traditional deep learning recurrent neural networks (RNNs) suffer from inefficient pulse recognition and poor recognition of pile-up nuclear pulses with short intervals between adjacent pulses. In this paper, a Transformer model with an attention mechanism as the core to recognize pile-up nuclear pulses is innovatively applied, aiming to provide a more accurate and efficient method for pile-up nuclear pulse recognition. Thus, it gives a better help for the spectrum correction with a high count rate.

Analysis of BIM in the Whole-Process Cost Management of Construction Projects

In order to improve the quality of project cost management, this paper uses BIM technology to analyze the whole-process project cost to improve its management effect, uses the method of digital processing nuclear pulse signal to conduct simulation analysis, and conducts preliminary simulation. Moreover, this paper discusses the characteristics of cost management data, analyzes the process of BIM in the whole-process cost management of construction projects, and analyzes the possibility of using pulse digital method to improve stability. In addition, this paper constructs the whole-process cost management of engineering projects based on BIM. Through the experimental research, it is verified that the whole-process cost management system based on BIM constructed in this paper has a good effect and can effectively improve the quality of cost management of construction projects.

Structural Design of Handicrafts Based on Dynamic Simulation Technology

In order to improve the effect of handicraft structure design, this study combines the dynamic simulation technology to build a handicraft structure design system and transmits data through dynamic simulation signals to improve the effectiveness of the interactive design of artworks. In order to provide a simpler and faster development process for interactive media applications, this study develops an interactive media art design system with a node-based visual programming model as the core processing logic. The digital Gaussian shaping method based on the programmable logic device can not only realize real-time Gaussian shaping of the nuclear pulse signal but also meet the needs of later function expansion, maintenance, and upgrade of the system. In addition, this study verifies the effectiveness of the handicraft structure design system based on dynamic simulation technology through the analysis of multiple sets of simulation data.

Design and characterization of third-order Sallen–Key digital filter in nuclear signal processing

The Gaussian filter shaping circuit is widely used in the nuclear pulse signal processing due to its good performance in amplitude extraction and pulse counting. A third-order Sallen–Key (3rd S–K) filter shaping circuit is designed based on a RC integrator and a second-order Sallen–Key (2nd S–K) circuit. According to the digital 3rd S–K, the transfer functions is derived in the Laplacian domain, and the numerical recurrence model is analyzed and researched, the purpose is to obtain its transfer function and amplitude–frequency response curve in the z-domain. For the simulation and actual sampling of the nuclear signal, digital shaping processing is performed at different parameters, three parameters (d, SNR, δ) are defined to compare and analyze the amplitude extraction, noise suppression and symmetry of the digital shaping method, which shows that as the shaping parameters increases, the digital shaping output noise suppression performance is better, the SNR increased from 49.25 to 64.21, the waveform is more symmetrical, the δ reduced from 34.05 to 0.22. At the same parameters, it is compared and analyzed with CR-RC3 and 2nd S–K shaping methods, according to the digital Gaussian shaping results, the 3rd S–K digital shaping method has better pulse amplitude extraction(d = 36.06%), noise suppression performance (SNR = 64.21) and waveform symmetry (δ = 0.22). Under different shaping methods, the energy resolution and pulse counting rate of the Fe characteristic X-ray energy spectrum are compared based on a Si-PIN detector. The results show that the 3rd S–K digital shaping method has better energy resolution performance and comprehensive performance indicators, which can be further applied for digital shaping of nuclear pulse signals.

Study of scintillation detector fault diagnosis based on ELM method

This paper proposes a method for scintillation detector fault diagnosis based on the Extreme Learning Machine (ELM) algorithm. A related characteristics database is established including the falling edge time, signal amplitude of nuclear pulse signals, and energy spectrum peak channel, low channel address count of energy spectrum signal under various operating conditions. Then a diagnosis model for scintillation detector is created by improved ELM algorithm which have changed the activation function of the hidden layers and modified the number of hidden layers. An experiment system is also constructed for collecting and validating fault data, the diagnostic experiment results show that this method can not only classify the faults of the failed detector, but also distinguish intelligently the severity of various faults.

Universal uncertainty estimation for nuclear detector signals with neural networks and ensemble learning

Characterizing uncertainty is a common issue in nuclear measurement and has important implications for reliable physical discovery. Traditional methods are either insufficient to cope with the heterogeneous nature of uncertainty or inadequate to perform well with unknown mathematical models. In this paper, we propose using multi-layer convolutional neural networks for empirical uncertainty estimation and feature extraction of nuclear pulse signals. This method is based on deep learning, a recent development of machine learning techniques, which learns the desired mapping function from training data and generalizes to unseen test data. Furthermore, ensemble learning is utilized to estimate the uncertainty originating from trainable parameters of the network and to improve the robustness of the whole model. To evaluate the performance of the proposed method, simulation studies, in comparison with curve fitting, investigate extensive conditions and show its universal applicability. Finally, a case study is made using data from a NICA-MPD electromagnetic calorimeter module exposed to a test beam at DESY, Germany. The uncertainty estimation method successfully detected out-of-distribution samples and also achieved good accuracy in time and energy measurements.

Pulsed Nuclear Space Propulsion and International Law: Some Preliminary

Pulsed Nuclear Space Propulsion, researched in the 1950s and 1960s by such eminent physicists as Freeman Dyson, Ted Taylor, Theodore von Karman, and Hans Bethe, involves propelling large spacecraft using compact nuclear explosions from specialized atomic devices. This technology is often known by the name of the Air Force project in which it was developed: Orion. It has long been believed that the 1962 Limited Test Ban Treaty prohibits the use of nuclear pulse space propulsion. After a survey of the Orion project and its results and a review of the applicable law, this Article concludes that language in the 1967 Outer Space Treaty may override the Test Ban agreement to permit non-weapons use of nuclear explosives for propulsion. With a new space race taking place and with important actors such as China not subject to the Test Ban Treaty at all, the subject of pulsed nuclear space propulsion deserves another look.