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, Available online , doi: 10.11884/HPLPB202436.230357
Abstract:
Lead cooled fast reactor has obvious advantages in fuel proliferation and nuclear waste treatment. For the Europe Lead-cooled System (ELSY), based on the “two-step method”, Monte Carlo software is used to generate few group component parameters, and after section correction, it is passed to the determining theory program MORPHY for core calculation. The effects of section modification and angle development order on the calculation accuracy were analyzed, and the effective multiplication factor, normalized flux level and control rod value of the ELSY core were quantified and compared. For different examples, transport correction and neutron multiplication effect correction were adopted, and the core calculation was developed with S4 order. The maximum deviation of effective multiplication factor was 38×10−5, the calculation deviation of control rod value was within 45×10−5, the maximum absolute deviation of normalized neutron flux density was 9.73%, and the average absolute deviation was less than 2%. The feasibility of MORPHY program in the physical analysis of lead-cooled fast reactor is preliminarily verified, which is of reference significance for the subsequent development and use of the program.
Lead cooled fast reactor has obvious advantages in fuel proliferation and nuclear waste treatment. For the Europe Lead-cooled System (ELSY), based on the “two-step method”, Monte Carlo software is used to generate few group component parameters, and after section correction, it is passed to the determining theory program MORPHY for core calculation. The effects of section modification and angle development order on the calculation accuracy were analyzed, and the effective multiplication factor, normalized flux level and control rod value of the ELSY core were quantified and compared. For different examples, transport correction and neutron multiplication effect correction were adopted, and the core calculation was developed with S4 order. The maximum deviation of effective multiplication factor was 38×10−5, the calculation deviation of control rod value was within 45×10−5, the maximum absolute deviation of normalized neutron flux density was 9.73%, and the average absolute deviation was less than 2%. The feasibility of MORPHY program in the physical analysis of lead-cooled fast reactor is preliminarily verified, which is of reference significance for the subsequent development and use of the program.
, Available online , doi: 10.11884/HPLPB202436.240031
Abstract:
The adder topology solid state modulator is a device that uses insulated gate bipolar transistors (IGBTs) to discharge the stored energy of capacitors to generate high voltage pulses. Compared with pulse forming network (PFN) type modulator, it has lots of advantages such as modularity, good stability, and long lifespan. However, the normal operation of IGBT requires the use of gate drive circuit to amplify the control signal, and the performance of the drive circuit directly affects the switching characteristics of the IGBT, ultimately affects the quality of pulse voltage, especially the turn-on jitter index of the drive circuit, which is one of the key factors affecting the pulse voltage repetition precision. Based on the operating characteristics of IGBT in the adder topology solid state modulator, the drive circuit was studied with the goal of improving pulse voltage repetition precision. The impact of turn-on jitter on voltage repetition precision was analyzed, the design principle was introduced, the drive circuit board was developed, and its working performance was experimentally tested using a discharge module. The test results indicate that the turn-on jitter of the drive circuit is 300 ps, which is three times better than commercial driving circuits. At the charging voltage of 1 kV, the discharge module discharges on a 0.5 Ω load, forming a pulse voltage with the rise time of 500 ns and the peak-to-peak value of turn-on jitter below 5 ns. When the desaturation fault occurs, the drive circuit can turn off the IGBT within 4 µs. This drive circuit meets the working requirements of high pulse repetition precision solid state modulators.
The adder topology solid state modulator is a device that uses insulated gate bipolar transistors (IGBTs) to discharge the stored energy of capacitors to generate high voltage pulses. Compared with pulse forming network (PFN) type modulator, it has lots of advantages such as modularity, good stability, and long lifespan. However, the normal operation of IGBT requires the use of gate drive circuit to amplify the control signal, and the performance of the drive circuit directly affects the switching characteristics of the IGBT, ultimately affects the quality of pulse voltage, especially the turn-on jitter index of the drive circuit, which is one of the key factors affecting the pulse voltage repetition precision. Based on the operating characteristics of IGBT in the adder topology solid state modulator, the drive circuit was studied with the goal of improving pulse voltage repetition precision. The impact of turn-on jitter on voltage repetition precision was analyzed, the design principle was introduced, the drive circuit board was developed, and its working performance was experimentally tested using a discharge module. The test results indicate that the turn-on jitter of the drive circuit is 300 ps, which is three times better than commercial driving circuits. At the charging voltage of 1 kV, the discharge module discharges on a 0.5 Ω load, forming a pulse voltage with the rise time of 500 ns and the peak-to-peak value of turn-on jitter below 5 ns. When the desaturation fault occurs, the drive circuit can turn off the IGBT within 4 µs. This drive circuit meets the working requirements of high pulse repetition precision solid state modulators.
, Available online , doi: 10.11884/HPLPB202436.230363
Abstract:
The classical Jiles-Atherton (J-A) equation has been modified through theoretical analysis, which enhances its adaptability under pulsed conditions. Hysteresis loops of Fe-based nanocrystalline cores are measured at different magnetization rates by using an experimental platform for pulsed magnetization properties. The genetic algorithm (GA) is used for J-A parameter identification under pulsed excitation, and the validity of the modified J-A equations is verified by fitting the algorithmically simulated hysteresis loops to the experimentally tested hysteresis loop dataset. Finally, the J-A parameter obtained by GA optimization are applied to the definition of magnetic core parameters in the field-circuit coupling model of the pulse transformer, the simulation and experimental errors when the primary voltage of the pulse transformer is 1.5 kV are analyzed. The results show that the pulse front error of the output waveform is 3.33% and the amplitude error is 2.91%, which is more accurate than the conventional nonlinear solving method of J-A parameter. This indicates that the optimized J-A parameter can be better applied to the modeling and simulation of magnetic-containing components in pulsed power systems.
The classical Jiles-Atherton (J-A) equation has been modified through theoretical analysis, which enhances its adaptability under pulsed conditions. Hysteresis loops of Fe-based nanocrystalline cores are measured at different magnetization rates by using an experimental platform for pulsed magnetization properties. The genetic algorithm (GA) is used for J-A parameter identification under pulsed excitation, and the validity of the modified J-A equations is verified by fitting the algorithmically simulated hysteresis loops to the experimentally tested hysteresis loop dataset. Finally, the J-A parameter obtained by GA optimization are applied to the definition of magnetic core parameters in the field-circuit coupling model of the pulse transformer, the simulation and experimental errors when the primary voltage of the pulse transformer is 1.5 kV are analyzed. The results show that the pulse front error of the output waveform is 3.33% and the amplitude error is 2.91%, which is more accurate than the conventional nonlinear solving method of J-A parameter. This indicates that the optimized J-A parameter can be better applied to the modeling and simulation of magnetic-containing components in pulsed power systems.
, Available online , doi: 10.11884/HPLPB202436.240010
Abstract:
The preparation of Tb3Al5O12 (TAG) phosphors was fabricated by the sol-gel method. Thermal analysis data confirm that an increase in the H3BO3 molar ratio correlates with a reduction in the transition temperature of the final phase. Concurrently, scanning electron microscopy revealed that an elevated H3BO3 molar ratio results in larger phosphor particle sizes. Under the excitation wavelength of 275 nm, the emission spectrum manifests multiple peaks within the 480-650 nm range, originating from the 5d→4f transitions of Tb3+ ions. Subsequently, the phosphor@SiO2 aerogel composite luminescent material was successfully synthesized through a combination of physical doping and a supercritical drying process. This composite luminescent material exhibited a substantial increase in the internal quantum yield, reaching 63.64% compared to the standalone phosphor. Excited by a 355 nm laser source, the phosphor@SiO2 aerogel composite luminescent material demonstrated the capability for wire-free, long-distance luminescence with commendable uniformity. These findings demonstrate the potential application prospects of the phosphor@SiO2 aerogel composite luminescent material in the domain of laser emergency lighting.
The preparation of Tb3Al5O12 (TAG) phosphors was fabricated by the sol-gel method. Thermal analysis data confirm that an increase in the H3BO3 molar ratio correlates with a reduction in the transition temperature of the final phase. Concurrently, scanning electron microscopy revealed that an elevated H3BO3 molar ratio results in larger phosphor particle sizes. Under the excitation wavelength of 275 nm, the emission spectrum manifests multiple peaks within the 480-650 nm range, originating from the 5d→4f transitions of Tb3+ ions. Subsequently, the phosphor@SiO2 aerogel composite luminescent material was successfully synthesized through a combination of physical doping and a supercritical drying process. This composite luminescent material exhibited a substantial increase in the internal quantum yield, reaching 63.64% compared to the standalone phosphor. Excited by a 355 nm laser source, the phosphor@SiO2 aerogel composite luminescent material demonstrated the capability for wire-free, long-distance luminescence with commendable uniformity. These findings demonstrate the potential application prospects of the phosphor@SiO2 aerogel composite luminescent material in the domain of laser emergency lighting.
, Available online , doi: 10.11884/HPLPB202436.230140
Abstract:
The Tm3+ gain medium with high doping concentration can improve the quantum efficiency of the laser through the cross relaxation process, but it also increases the energy loss caused by energy up-conversion and limits the improvement of laser efficiency. The fluorescence characteristics and laser performance of Tm:SrF2 crystal are studied. Under laser-diode (LD) end-pumping, a continuous-wave laser with a maximum output power of 2.99 W and a slope efficiency of up to 82.1% is realized. The pump threshold of the laser is 0.81 W, and the center wavelength is 1851 nm. Electro-optic Q-switching of the Tm:SrF2 laser is demonstrated. At the repetition rate of 500 Hz, a maximum pulse energy of 1.02 mJ and a minimum pulse width of 45 ns are achieved, resulting in a peak power of 22.67 kW. The experimental results indicate that the Tm:SrF2 laser based on LD pumping has very high efficiency and is expected to be an ideal pump source for optical parametric oscillators (OPOs) and optical parametric amplifiers (OPAs).
The Tm3+ gain medium with high doping concentration can improve the quantum efficiency of the laser through the cross relaxation process, but it also increases the energy loss caused by energy up-conversion and limits the improvement of laser efficiency. The fluorescence characteristics and laser performance of Tm:SrF2 crystal are studied. Under laser-diode (LD) end-pumping, a continuous-wave laser with a maximum output power of 2.99 W and a slope efficiency of up to 82.1% is realized. The pump threshold of the laser is 0.81 W, and the center wavelength is 1851 nm. Electro-optic Q-switching of the Tm:SrF2 laser is demonstrated. At the repetition rate of 500 Hz, a maximum pulse energy of 1.02 mJ and a minimum pulse width of 45 ns are achieved, resulting in a peak power of 22.67 kW. The experimental results indicate that the Tm:SrF2 laser based on LD pumping has very high efficiency and is expected to be an ideal pump source for optical parametric oscillators (OPOs) and optical parametric amplifiers (OPAs).
, Available online , doi: 10.11884/HPLPB202436.240004
Abstract:
The RbTiOPO4 crystal Raman emission at high-order Stokes with 271 cm−1 shift driven by an end-pumped passively Q-switched laser was demonstrated. The Nd:YAG and Cr4+:YAG bonding design was used to reduce the intracavity loss and make the laser system compact, so as to raise the intracavity photon density, which proved helpful for the conversion of Raman shift to high-order Stokes light. The first-Stokes laser with different Raman shifts is designed to oscillate in different cavities, and the first-Stokes laser with 687 cm−1 shift is suppressed by using the difference in cavity mode matching with the fundamental laser, and the fifth-order Stokes laser with 271 cm−1 shift is obtained. Under the pump power of 8.1 W, a 1 244 nm wavelength laser with an average output power of 230 mW was obtained, and the corresponding pulse width and pulse frequency repetition were 2.9 ns and 11.7 kHz, respectively. The 1 244 nm laser wavelength perfectly matched the OH−1 absorption peak in water, which could have significant applications in fields such as surface vegetation and planetary water detection.
The RbTiOPO4 crystal Raman emission at high-order Stokes with 271 cm−1 shift driven by an end-pumped passively Q-switched laser was demonstrated. The Nd:YAG and Cr4+:YAG bonding design was used to reduce the intracavity loss and make the laser system compact, so as to raise the intracavity photon density, which proved helpful for the conversion of Raman shift to high-order Stokes light. The first-Stokes laser with different Raman shifts is designed to oscillate in different cavities, and the first-Stokes laser with 687 cm−1 shift is suppressed by using the difference in cavity mode matching with the fundamental laser, and the fifth-order Stokes laser with 271 cm−1 shift is obtained. Under the pump power of 8.1 W, a 1 244 nm wavelength laser with an average output power of 230 mW was obtained, and the corresponding pulse width and pulse frequency repetition were 2.9 ns and 11.7 kHz, respectively. The 1 244 nm laser wavelength perfectly matched the OH−1 absorption peak in water, which could have significant applications in fields such as surface vegetation and planetary water detection.
, Available online , doi: 10.11884/HPLPB202436.230442
Abstract:
Impacted by various factors such as geographical position, sun and atmospheric environment, it is impossible to obtain the real images of space targets under various postures and illumination conditions, let alone under the interaction between laser, sun and background light. In this paper, a real-time target image generation method under multi-light source irradiation is proposed. This method is based on the modern graphics card programming technique and frame caching object advantages. At the GPU (Graphics Processing Unit) side, shader language is used to efficiently calculate target brightness values and enhance realism under the influence of multi-light source. The open-source 3D graphics engine named OSG (Open Scene Graph) helps support 3D model files of various formats and improve the compatibility with the domestic Kirin operating system as well as common battlefield situation display software. Simulation experiments demonstrate the effectiveness and superiority of the proposed method.
Impacted by various factors such as geographical position, sun and atmospheric environment, it is impossible to obtain the real images of space targets under various postures and illumination conditions, let alone under the interaction between laser, sun and background light. In this paper, a real-time target image generation method under multi-light source irradiation is proposed. This method is based on the modern graphics card programming technique and frame caching object advantages. At the GPU (Graphics Processing Unit) side, shader language is used to efficiently calculate target brightness values and enhance realism under the influence of multi-light source. The open-source 3D graphics engine named OSG (Open Scene Graph) helps support 3D model files of various formats and improve the compatibility with the domestic Kirin operating system as well as common battlefield situation display software. Simulation experiments demonstrate the effectiveness and superiority of the proposed method.
, Available online , doi: 10.11884/HPLPB202436.230432
Abstract:
Aiming at the difficulty of predicting the length of rock-breaking arc plasma channel by high voltage pulse discharge, a comprehensive test platform for rock-breaking arc plasma channel by high voltage pulse discharge was constructed. The development characteristics and typical current and voltage parameters of arc plasma channel under granite-tap water combined medium were measured, and the broken region formed on the rock surface under different electrode spacing and pulse discharge times was extracted. Based on the energy balance equation, the impedance model of the arc plasma channel in rock is established. The approximate optimal solution of the impedance model parameters is obtained by iterative optimization algorithm. The relative error between the calculated results and the experimental results is less than 7%. Based on the optimized parameters, the length of plasma channel is predicted by the measured current and voltage data. The absolute error between the plasma channel length predicted by the model and the measured value is in the order of mm, and the relative error is less than 10%, which provides theoretical support for the matching design of power-electrode load in the high-voltage pulse discharge rock breaking system.
Aiming at the difficulty of predicting the length of rock-breaking arc plasma channel by high voltage pulse discharge, a comprehensive test platform for rock-breaking arc plasma channel by high voltage pulse discharge was constructed. The development characteristics and typical current and voltage parameters of arc plasma channel under granite-tap water combined medium were measured, and the broken region formed on the rock surface under different electrode spacing and pulse discharge times was extracted. Based on the energy balance equation, the impedance model of the arc plasma channel in rock is established. The approximate optimal solution of the impedance model parameters is obtained by iterative optimization algorithm. The relative error between the calculated results and the experimental results is less than 7%. Based on the optimized parameters, the length of plasma channel is predicted by the measured current and voltage data. The absolute error between the plasma channel length predicted by the model and the measured value is in the order of mm, and the relative error is less than 10%, which provides theoretical support for the matching design of power-electrode load in the high-voltage pulse discharge rock breaking system.
, Available online , doi: 10.11884/HPLPB202436.230423
Abstract:
In a previous work, a two-stage microstructure was proposed and demonstrated to be able to sharply improve surface flashover voltage of polymer insulators in vacuum. In this paper, the two-stage microstructure was separated into two sub-structures, i.e., surface micro-groove structure and surface micro-hole structure, to study the voltage improvement mechanism in the two-stage microstructure. Through the synthesis of a composite material, laser treatment and acid corrosion, the two-stage microstructure was prepared as well as the two sub-structures. Flashover test of the insulators with the three kinds of surface structures showed that construction of micro grooves and micro holes on the surface of insulators could both enhance the surface flashover strength and their combination could further enhance the flashover strength. The results indicate that through proper combination of different kinds of surface structures multiple suppression of the flashover could be achieved and the surface flashover voltage could be further improved.
In a previous work, a two-stage microstructure was proposed and demonstrated to be able to sharply improve surface flashover voltage of polymer insulators in vacuum. In this paper, the two-stage microstructure was separated into two sub-structures, i.e., surface micro-groove structure and surface micro-hole structure, to study the voltage improvement mechanism in the two-stage microstructure. Through the synthesis of a composite material, laser treatment and acid corrosion, the two-stage microstructure was prepared as well as the two sub-structures. Flashover test of the insulators with the three kinds of surface structures showed that construction of micro grooves and micro holes on the surface of insulators could both enhance the surface flashover strength and their combination could further enhance the flashover strength. The results indicate that through proper combination of different kinds of surface structures multiple suppression of the flashover could be achieved and the surface flashover voltage could be further improved.
, Available online , doi: 10.11884/HPLPB202436.230410
Abstract:
The study of vacuum surface flashover along the insulator ring was carried out. An experimental platform for vacuum insulator stack was built. The influence of flashover among insulator ring on the voltage of the vacuum insulator stack was evaluated by equivalent circuit model. Vacuum surface flashover along the three kinds of material insulator stacks were carried out, which verify the availability and reliability of the experimental platform. This work provides a reference for the engineering research of the vacuum insulator stack of pulse power device, and also provides an experimental platform for research of new insulation materials.
The study of vacuum surface flashover along the insulator ring was carried out. An experimental platform for vacuum insulator stack was built. The influence of flashover among insulator ring on the voltage of the vacuum insulator stack was evaluated by equivalent circuit model. Vacuum surface flashover along the three kinds of material insulator stacks were carried out, which verify the availability and reliability of the experimental platform. This work provides a reference for the engineering research of the vacuum insulator stack of pulse power device, and also provides an experimental platform for research of new insulation materials.
, Available online , doi: 10.11884/HPLPB202436.230337
Abstract:
Based on the requirement of high current multi-pulse accelerator, the surface flashover characteristics of cross-linked polystyrene (XLPS) material under burst multi-pulse in vacuum were studied experimentally. Vacuum surface flashover experiments were carried out with XLPS samples placed in flat electrodes under single pulse and three pulses with interval of 500 ns. Special phenomena such as continuous decrease of equivalent impedance of vacuum surface before flashover and continuous maintenance of flashover channel after pulse end were observed, and statistical data of vacuum surface flashover of XLPS materials under corresponding conditions were obtained. On the basis of experiments, the flashover characteristics of XLPS in vacuum under high repetition rate multi-pulse loading are analyzed, which provides experimental basis for insulation design of high repetition rate multi-pulse accelerator.
Based on the requirement of high current multi-pulse accelerator, the surface flashover characteristics of cross-linked polystyrene (XLPS) material under burst multi-pulse in vacuum were studied experimentally. Vacuum surface flashover experiments were carried out with XLPS samples placed in flat electrodes under single pulse and three pulses with interval of 500 ns. Special phenomena such as continuous decrease of equivalent impedance of vacuum surface before flashover and continuous maintenance of flashover channel after pulse end were observed, and statistical data of vacuum surface flashover of XLPS materials under corresponding conditions were obtained. On the basis of experiments, the flashover characteristics of XLPS in vacuum under high repetition rate multi-pulse loading are analyzed, which provides experimental basis for insulation design of high repetition rate multi-pulse accelerator.
, Available online , doi: 10.11884/HPLPB202436.230392
Abstract:
The breakdown characteristics of trigger gap for the pre-ionization switch in N2, the mixture of N2 and SF6 and SF6 atmosphere under positive and negative pulse were investigated for the higher voltage grade and bipolarity application. The relationships between the breakdown voltage and delay time of the pre-ionization gap and the pressure of different kinds of gases were obtained, and the breakdown characteristics were compared for the pre-ionization gap under positive and negative polarities. The results of the experiment demonstrated that the breakdown process of the gap in N2 was more stable, and the linearity of breakdown voltage varying with pressure in N2 was the best among the three kinds of gases. The breakdown voltage was saturated only in SF6 with the increase of gas pressure. The breakdown voltage of the gap under negative polarity was higher than that under the positive at some certain values of the pressure, and this phenomenon might suggest that there was a polarity effect upon the breakdown process of pre-ionization gap. Compared with the mixture and N2, the absolute differences between negative and positive polarity for both breakdown voltage and delay time in SF6 were relatively higher. N2 should be preferred as the insulating medium for the pre-ionization gap to reduce the synchronization delay difference of the bipolar self-triggered switches. The polarity effect of the pre-ionization gap and the distinctions among the different kinds of insulated gas medium should be paid more attention in engineering applications for the pre-ionization gap.
The breakdown characteristics of trigger gap for the pre-ionization switch in N2, the mixture of N2 and SF6 and SF6 atmosphere under positive and negative pulse were investigated for the higher voltage grade and bipolarity application. The relationships between the breakdown voltage and delay time of the pre-ionization gap and the pressure of different kinds of gases were obtained, and the breakdown characteristics were compared for the pre-ionization gap under positive and negative polarities. The results of the experiment demonstrated that the breakdown process of the gap in N2 was more stable, and the linearity of breakdown voltage varying with pressure in N2 was the best among the three kinds of gases. The breakdown voltage was saturated only in SF6 with the increase of gas pressure. The breakdown voltage of the gap under negative polarity was higher than that under the positive at some certain values of the pressure, and this phenomenon might suggest that there was a polarity effect upon the breakdown process of pre-ionization gap. Compared with the mixture and N2, the absolute differences between negative and positive polarity for both breakdown voltage and delay time in SF6 were relatively higher. N2 should be preferred as the insulating medium for the pre-ionization gap to reduce the synchronization delay difference of the bipolar self-triggered switches. The polarity effect of the pre-ionization gap and the distinctions among the different kinds of insulated gas medium should be paid more attention in engineering applications for the pre-ionization gap.
, Available online , doi: 10.11884/HPLPB202436.240036
Abstract:
The pseudospark switch works in the left branch of Paschen curve with low gas pressure, and it has the advantages of ns-level breakdown time, 100 kA-level pulse current and long lifetime. High pulse repetition frequency (PRF) pseudospark switch are widely used in both civil and military fields. This paper focuses on the double-pulse trigger structure and presents the design of a switch with this structure, which is tested with 10 kV anode voltage for different gas pressure, pre-trigger voltage and main trigger voltage. The corresponding relationship between the gas pressure, the two trigger voltages and trigger current are calculated respectively. In addition, the influence of pre-trigger and main trigger pulses on the trigger process is analysed. The results show that the minimum trigger voltage is only 100 V, and the switch can work stably with high repetition frequency.
The pseudospark switch works in the left branch of Paschen curve with low gas pressure, and it has the advantages of ns-level breakdown time, 100 kA-level pulse current and long lifetime. High pulse repetition frequency (PRF) pseudospark switch are widely used in both civil and military fields. This paper focuses on the double-pulse trigger structure and presents the design of a switch with this structure, which is tested with 10 kV anode voltage for different gas pressure, pre-trigger voltage and main trigger voltage. The corresponding relationship between the gas pressure, the two trigger voltages and trigger current are calculated respectively. In addition, the influence of pre-trigger and main trigger pulses on the trigger process is analysed. The results show that the minimum trigger voltage is only 100 V, and the switch can work stably with high repetition frequency.
, Available online , doi: 10.11884/HPLPB202436.240040
Abstract:
The working characteristics of the hydrogen thyratron and the optimization effect of the potential equalization treatment are investigated experimentally. The experiments show that the heating voltage has great influence on the working characteristics of hydrogen thyratron, on the premise of no self-discharge phenomenon, using higher heating voltage can obtain better conduction performance. The differences of trigger pulses and anode voltages have little effect on the conduction performance of hydrogen thyratron. Using resistors to equalize the voltage of hydrogen thyratron can make the voltage distribution more uniform and alleviate the phenomenon of self-discharge. The research provides reference and guidance for the use of hydrogen thyratron.
The working characteristics of the hydrogen thyratron and the optimization effect of the potential equalization treatment are investigated experimentally. The experiments show that the heating voltage has great influence on the working characteristics of hydrogen thyratron, on the premise of no self-discharge phenomenon, using higher heating voltage can obtain better conduction performance. The differences of trigger pulses and anode voltages have little effect on the conduction performance of hydrogen thyratron. Using resistors to equalize the voltage of hydrogen thyratron can make the voltage distribution more uniform and alleviate the phenomenon of self-discharge. The research provides reference and guidance for the use of hydrogen thyratron.
, Available online , doi: 10.11884/HPLPB202436.230347
Abstract:
To meet the requirements of multi-channel precise synchronous trigger switch, photo conductive semiconductor switch (PCSS) is combined with V/N gas switch, which takes advantage of the photoelectric isolation, low trigger threshold, low delay time jitter and photoelectric isolation of PCSS, as well as the advantages of high operating voltage and strong load capacity of V/N gas switch. The core of the combination of the two switches is that the structural parameters of the V/N gas switch match the parameters of the PCSS trigger loop. The structural capacitance, trigger loop oscillation parameters and switching electric field distribution of the V/N gas switch are analyzed and calculated. The relationship between the structural capacitance of the V/N gas switch and the oscillation loop composed of PCSS and series inductors is studied. The self-breakdown voltage curve, on-delay time and delay time jitter of the switch under different under voltage ratios are obtained. The performance of the V/N gas switch for PCSS triggering is preliminarily verified.
To meet the requirements of multi-channel precise synchronous trigger switch, photo conductive semiconductor switch (PCSS) is combined with V/N gas switch, which takes advantage of the photoelectric isolation, low trigger threshold, low delay time jitter and photoelectric isolation of PCSS, as well as the advantages of high operating voltage and strong load capacity of V/N gas switch. The core of the combination of the two switches is that the structural parameters of the V/N gas switch match the parameters of the PCSS trigger loop. The structural capacitance, trigger loop oscillation parameters and switching electric field distribution of the V/N gas switch are analyzed and calculated. The relationship between the structural capacitance of the V/N gas switch and the oscillation loop composed of PCSS and series inductors is studied. The self-breakdown voltage curve, on-delay time and delay time jitter of the switch under different under voltage ratios are obtained. The performance of the V/N gas switch for PCSS triggering is preliminarily verified.
, Available online , doi: 10.11884/HPLPB202436.230420
Abstract:
Flash X-ray photography technology has important scenarios in military and civil fields. According to the requirement of high repetition rate of the linear induction a ccelerator, we put foruarc a pulse power source scheme based on tri-coaxial cable Blumlein lines drivien by hydrogen thyratron. A tri-coaxial cable was designed and developed. The conduction characteristics of hydrogen thyratron were studied. The verification setup for the pulse power source was built. The experimental research on kHz repetition rate pulse power source and kHz repetition rate pulse power source driving induction cavity was carried out. The results show that the tri-coaxial cable Blumlein lines pulse power source driven by hydrogen thyratron can realize the kHz repetition rate square wave output with excellent waveform quality.
Flash X-ray photography technology has important scenarios in military and civil fields. According to the requirement of high repetition rate of the linear induction a ccelerator, we put foruarc a pulse power source scheme based on tri-coaxial cable Blumlein lines drivien by hydrogen thyratron. A tri-coaxial cable was designed and developed. The conduction characteristics of hydrogen thyratron were studied. The verification setup for the pulse power source was built. The experimental research on kHz repetition rate pulse power source and kHz repetition rate pulse power source driving induction cavity was carried out. The results show that the tri-coaxial cable Blumlein lines pulse power source driven by hydrogen thyratron can realize the kHz repetition rate square wave output with excellent waveform quality.
, Available online , doi: 10.11884/HPLPB202436.240045
Abstract:
This paper proposes a design method for a high-power pulsed power supply for YAG laser systems, which is capable of realizing high-energy repetitive pulse with flexible voltage regulations. The power supply consists of an LC resonant converter as the charging network and a thyristor-based pulse forming network. Based on the proposed design approach, a 7 kW prototype is developed, which is able to output maximum voltage of 2.2 kV with a repetitive frequency ranged from 1 to 10 Hz. Moreover, the developed power supply is able to release up to 700 J of the energy on the xenon lamp.
This paper proposes a design method for a high-power pulsed power supply for YAG laser systems, which is capable of realizing high-energy repetitive pulse with flexible voltage regulations. The power supply consists of an LC resonant converter as the charging network and a thyristor-based pulse forming network. Based on the proposed design approach, a 7 kW prototype is developed, which is able to output maximum voltage of 2.2 kV with a repetitive frequency ranged from 1 to 10 Hz. Moreover, the developed power supply is able to release up to 700 J of the energy on the xenon lamp.
, Available online , doi: 10.11884/HPLPB202436.230295
Abstract:
LC series resonant high voltage constant current charging power supply can realize high efficiency and fast charging of the capacitor and has an excellent capacity of anti-load short-circuit, hence it has extensive application prospects in high repetition frequency pulsed power systems. The efficiency of the charging power supply is a crucial factor to determine the ability of the system to operate at repetition rate. Improving efficiency is the primary goal of designing high-voltage capacitor charging power supply. According to the working principle of LC series resonant circuit, it is analyzed that the operating mode of power supply, the switching frequency of the inverter bridge and the distribution parameters of the high-frequency transformer are the main ingredients affecting the efficiency. For a DC power supply with a power of 10 kW and an output voltage of 40 kV, the main circuit parameters were calculated and the circuit model was established using Pspice to verify its accuracy. The soft switching technology was used to reduce the switching loss, and the high frequency transformer with smaller distribution parameters was designed to further improve the efficiency. On this basis, the overall structure design of the power supply was completed. Finally, the charging characteristics of the power supply were tested. Experimental tests indicate that the power supply can charge a 0.1 µF capacitor to 39.5 kV within 37 ms, and the charging efficiency of the power supply is 87.1%.
LC series resonant high voltage constant current charging power supply can realize high efficiency and fast charging of the capacitor and has an excellent capacity of anti-load short-circuit, hence it has extensive application prospects in high repetition frequency pulsed power systems. The efficiency of the charging power supply is a crucial factor to determine the ability of the system to operate at repetition rate. Improving efficiency is the primary goal of designing high-voltage capacitor charging power supply. According to the working principle of LC series resonant circuit, it is analyzed that the operating mode of power supply, the switching frequency of the inverter bridge and the distribution parameters of the high-frequency transformer are the main ingredients affecting the efficiency. For a DC power supply with a power of 10 kW and an output voltage of 40 kV, the main circuit parameters were calculated and the circuit model was established using Pspice to verify its accuracy. The soft switching technology was used to reduce the switching loss, and the high frequency transformer with smaller distribution parameters was designed to further improve the efficiency. On this basis, the overall structure design of the power supply was completed. Finally, the charging characteristics of the power supply were tested. Experimental tests indicate that the power supply can charge a 0.1 µF capacitor to 39.5 kV within 37 ms, and the charging efficiency of the power supply is 87.1%.
, Available online , doi: 10.11884/HPLPB202436.240020
Abstract:
Flash X-ray radiography is often used to photograph the internal structure and hydrodynamic behavior of high-speed moving objects, and has gradually expanded to the fields of industrial flaw detection, precision system state detection and so on. This paper summarizes the research process and progress of small flash X-ray machine (SFXM), relating to four main technical routes of Marx generator, pulse forming line, fast pulse linear transformer, high-voltage transformer, and two key components of X-ray diode and switches. The research status of small flash X-ray radiography system is discussed, and the shortcomings of mature commercial small X-ray machines abroad and domestic commercial products are explored, The development trend of SFXM in the future is analyzed, which provides reference and basis for the research and development of SFXM and the exploration of commercial popularization.
Flash X-ray radiography is often used to photograph the internal structure and hydrodynamic behavior of high-speed moving objects, and has gradually expanded to the fields of industrial flaw detection, precision system state detection and so on. This paper summarizes the research process and progress of small flash X-ray machine (SFXM), relating to four main technical routes of Marx generator, pulse forming line, fast pulse linear transformer, high-voltage transformer, and two key components of X-ray diode and switches. The research status of small flash X-ray radiography system is discussed, and the shortcomings of mature commercial small X-ray machines abroad and domestic commercial products are explored, The development trend of SFXM in the future is analyzed, which provides reference and basis for the research and development of SFXM and the exploration of commercial popularization.
, Available online , doi: 10.11884/HPLPB202436.230360
Abstract:
To increase the output voltage and reduce the volume and cost of the high voltage damped oscillator, a 4×4 stage self-triggering Marx structure damped oscillator model is established in this paper. In this model, the main switch of each stage adopts series IGBTs module based on capacitor trigger mode. Only one isolated signal is provided to control the turn-on and turn-off of the primary discharge switch tube. The grid of the adjacent discharge tube is automatically charged and discharged through the interstage capacitance to make it turn-on and turn-off. The model improves the working voltage of Marx single stage and simplifies the driving circuit of each stage, and solves the problem of dynamic and static voltage equalization of switching tube by adding buffer circuit. Based on this topology, a prototype of a high-voltage damped oscillator is built, which outputs 16 kV damped oscillation waveform with a frequency of 1 MHz on an inductive load. The rise time of the waveform is about 75 ns, and the repetition frequency is 500 Hz. The prototype is small in size and stable in operation, which verifies the feasibility of the scheme.
To increase the output voltage and reduce the volume and cost of the high voltage damped oscillator, a 4×4 stage self-triggering Marx structure damped oscillator model is established in this paper. In this model, the main switch of each stage adopts series IGBTs module based on capacitor trigger mode. Only one isolated signal is provided to control the turn-on and turn-off of the primary discharge switch tube. The grid of the adjacent discharge tube is automatically charged and discharged through the interstage capacitance to make it turn-on and turn-off. The model improves the working voltage of Marx single stage and simplifies the driving circuit of each stage, and solves the problem of dynamic and static voltage equalization of switching tube by adding buffer circuit. Based on this topology, a prototype of a high-voltage damped oscillator is built, which outputs 16 kV damped oscillation waveform with a frequency of 1 MHz on an inductive load. The rise time of the waveform is about 75 ns, and the repetition frequency is 500 Hz. The prototype is small in size and stable in operation, which verifies the feasibility of the scheme.
, Available online , doi: 10.11884/HPLPB202436.240053
Abstract:
This review article aims at summarizing the basic principles of circuit methods used in compact pulsed-power generators. The concept of energy storage and voltage adding are explained followed by the descriptions on switching unit design and control signal generation. Some examples of applications of these circuit methods are given, including Marx circuit using capacitor energy storage, Marx circuit using inductive energy storage, Marx circuit using hybrid energy storage, linear transformer driver (LTD) circuit using capacitive energy storage and LTD circuit using inductive energy storage.
This review article aims at summarizing the basic principles of circuit methods used in compact pulsed-power generators. The concept of energy storage and voltage adding are explained followed by the descriptions on switching unit design and control signal generation. Some examples of applications of these circuit methods are given, including Marx circuit using capacitor energy storage, Marx circuit using inductive energy storage, Marx circuit using hybrid energy storage, linear transformer driver (LTD) circuit using capacitive energy storage and LTD circuit using inductive energy storage.
, Available online , doi: 10.11884/HPLPB202436.230353
Abstract:
The high-precision synchronization system is one of the key factors for the accelerator to generate high-quality beams. Based on the existing continuous laser carrier synchronization system of Tsinghua University, this paper analyzes the long-term drift of the reference microwave signal phase difference between different receiving ends, that is, the slow drift of the synchronization system. An electro-optic modulator (EOM) bias voltage control method based on the amplitude of the reference microwave signal at the receiving end was proposed to suppress the slow drift. After adopting this method, the slow drift of the L-band (1300 MHz) synchronization system of Tsinghua University’s VHF band photocathode electron gun test platform was suppressed to 10.45 fs@24 h, and the slow drift of the S-band (2 856 MHz) synchronization system of Tsinghua University’s Thomson Scattering Facility (TTX) was suppressed to 10.53 fs@24 h. Moreover, this method can make the entire synchronization system work in a room temperature environment, effectively improving the adaptability of the synchronization system to the working environment temperature.
The high-precision synchronization system is one of the key factors for the accelerator to generate high-quality beams. Based on the existing continuous laser carrier synchronization system of Tsinghua University, this paper analyzes the long-term drift of the reference microwave signal phase difference between different receiving ends, that is, the slow drift of the synchronization system. An electro-optic modulator (EOM) bias voltage control method based on the amplitude of the reference microwave signal at the receiving end was proposed to suppress the slow drift. After adopting this method, the slow drift of the L-band (1300 MHz) synchronization system of Tsinghua University’s VHF band photocathode electron gun test platform was suppressed to 10.45 fs@24 h, and the slow drift of the S-band (2 856 MHz) synchronization system of Tsinghua University’s Thomson Scattering Facility (TTX) was suppressed to 10.53 fs@24 h. Moreover, this method can make the entire synchronization system work in a room temperature environment, effectively improving the adaptability of the synchronization system to the working environment temperature.
, Available online , doi: 10.11884/HPLPB202436.230316
Abstract:
The structural models of Si-doped glow discharge polymer (Si-GDP) were established using reactive force field molecular dynamics simulation (ReaxFF MD), and the effects of silicon content, hydrogen content, and density on its hybrid carbon bonding and mechanical properties were investigated. The results show that with the silicon content increasing, the molecules tend to form a silicon-containing macromolecule, and the types and number of small molecules decrease, the silicon content improves the mechanical properties by promoting the binding of carbon and silicon atoms and inhibiting the formation of end-group sp3CH3. Besides, species such as ·C2H3, ·C3H5 and ·Si(CH3)3 were found during the formation of Si-GDP, which were in good agreement with the thin film deposition experiment of glow discharge polymer. The hydrogen content is measured as the atomic ratio of hydrogen to carbon and silicon, as the ratio grows, the number of model molecules did not change significantly, the ratio of sp3C and sp3CH3 increased, and the hydrogen content decreased the mechanical properties mainly by promoting the formation of sp3CH3. With the density increasing, the number of molecular species in the model did not change much, and the proportion of sp2C in the model was significantly increased, while the proportion of sp3C was slightly increased, the mechanical properties of Si-doped hydrogenated amorphous carbon were mainly improved by increasing the proportion of sp2C. This study provides an example for constructing Si-GDP by ReaxFF MD, and may provide a new method and reference for evaluating the structure and mechanical properties of Si-GDP.
The structural models of Si-doped glow discharge polymer (Si-GDP) were established using reactive force field molecular dynamics simulation (ReaxFF MD), and the effects of silicon content, hydrogen content, and density on its hybrid carbon bonding and mechanical properties were investigated. The results show that with the silicon content increasing, the molecules tend to form a silicon-containing macromolecule, and the types and number of small molecules decrease, the silicon content improves the mechanical properties by promoting the binding of carbon and silicon atoms and inhibiting the formation of end-group sp3CH3. Besides, species such as ·C2H3, ·C3H5 and ·Si(CH3)3 were found during the formation of Si-GDP, which were in good agreement with the thin film deposition experiment of glow discharge polymer. The hydrogen content is measured as the atomic ratio of hydrogen to carbon and silicon, as the ratio grows, the number of model molecules did not change significantly, the ratio of sp3C and sp3CH3 increased, and the hydrogen content decreased the mechanical properties mainly by promoting the formation of sp3CH3. With the density increasing, the number of molecular species in the model did not change much, and the proportion of sp2C in the model was significantly increased, while the proportion of sp3C was slightly increased, the mechanical properties of Si-doped hydrogenated amorphous carbon were mainly improved by increasing the proportion of sp2C. This study provides an example for constructing Si-GDP by ReaxFF MD, and may provide a new method and reference for evaluating the structure and mechanical properties of Si-GDP.
