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1

Detektory gazowe – drugie życie w badaniach termojądrowych

Chernyshova Maryna, Kowalska-Strzęciwilk Ewa

Postępy Techniki Jądrowej

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2023

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z. 4

18--33

PL

Poszukiwanie najnowszych technologii w dziedzinie diagnostyki plazmy jest napędzane rosnącymi wymogami dotyczącymi stabilności materiałów, pod wpływem rożnego rodzaju promieniowania, stosowanych w budowie i eksploatacji urządzeń termojądrowych. W miarę postępu tych urządzeń, badanie procesów zachodzących podczas oddziaływania promieniowania z materią staje się coraz bardziej istotne. W tym kontekście poszukiwanie innowacyjnych technologii, zwłaszcza w detekcji obrazowej promieni X, staje się niezbędne dla nowej generacji reaktorów, takich jak ITER, oraz przyszłej elektrowni termojądrowej DEMO. Współcześnie powszechnie używane detektory promieniowania rentgenowskiego stosowane w takich warunkach stoją przed znaczącym wyzwaniem – szybką degradacją pod wpływem intensywnych strumieni neutronów charakterystycznych dla urządzeń termojądrowych. Kwestia ta wytycza potrzebę opracowania nowej technologii detekcji promieniowania rentgenowskiego dostosowanej do unikalnych wymagań obecnych oraz przyszłych urządzeń termojądrowych, z naciskiem na ich odporność i trwałość. Mimo iż tradycyjnie detektory półprzewodnikowe są wciąż wykorzystywane do rejestracji miękkich promieni rentgenowskich (z ang. SXR – Soft X-Ray), to istnieje rosnące zainteresowanie badaniem detektorów gazowych w układach plazmowych, jako bardziej obiecujących kandydatów ze względu na ich inherentną odporność na promieniowanie neutronowe. Wśród nowej klasy detektorów gazowych szczególnym wyróżnieniem cieszy się detektor typu GEM (z ang. GEM – Gas Electron Multiplier). Detektor tej klasy wykazuje wysoki współczynnik wzmocnienia dla pierwotnego ładunku pochodzącego z absorpcji fotonów, co między innymi czyni go właściwym wyborem do zastosowań w przyszłych reaktorach termojądrowych.

EN

The search for the latest technologies in the field of plasma diagnostics is driven by increasing requirements for material stability under the influence of various types of radiation used in the construction and operation of thermonuclear devices. As these devices advance, studying the processes that occur during radiation-matter interactions becomes increasingly important. In this context, the search for innovative technologies, especially in X-ray imaging detection, becomes essential for future reactors such as ITER and the future thermonuclear power plant DEMO. Currently widely used X-ray radiation detectors used in such conditions face a significant challenge - rapid degradation under the influence of intense neutron flux characteristic of thermonuclear devices. This problem necessitates the development of new X-ray detection technology tailored to the unique requirements of current and future thermonuclear devices, with a focus on their resistance and durability. Although semiconductor detectors are traditionally used for soft X-ray (SXR) detection, there is growing interest in studying gas detectors for plasma devices as more promising candidates due to their inherent resistance to neutron radiation. Among the new class of gas detectors, the Gas Electron Multiplier (GEM) type detector is particularly notable. This type of detector exhibits a high gain coefficient for the primary charge resulting from photon absorption, making it, among other things, a noteworthy choice for applications in future thermonuclear reactors.

2

Diagnostic systems for the nuclear fusion and plasma research in the PF-24 plasma focus laboratory at the IFJ PAN

Marciniak Ł., Wójcik-Gargula A., Kulińska A., Bielecki J., Wiącek U.

Nukleonika

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2016

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Vol. 61, No. 4

413--418

EN

This paper presents a set of diagnostics dedicated to PF-24 – new medium size – plasma focus (PF) device built and operated at the Institute of Nuclear Physics Polish Academy of Sciences (IFJ PAN). The PF-24 can operate at energy level up to 93 kJ and charging voltage up to 40 kV. Each condenser is connected with a specially designed spark gap with a very small jitter, which ensures a high efficiency and a low current rise time. The working parameters of PF-24 generator make it a suitable tool for testing new detection systems to be used in fusion research. Four types of such detection systems are presented in this article: three diagnostic systems used to measure electric quantities (Rogowski coil, magnetic probe, capacitance probe), neutron counter based on beryllium activation, fast neutron pinhole camera based on small-area BCF-12 plastic scintillation detectors and high-speed four-frame soft X-ray camera with microchannel plate.

3

Temporal distribution of linear densities of the plasma column in a plasma focus discharge

Cikhardtova B., Kubeš P., Cikhardt J., Paduch M., Zielinska E., Kravárik J., Řezáč K., Kortanek J., Šíla O.

Nukleonika

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2015

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Vol. 60, No. 2

315--318

EN

Experiments were carried out on the PF-1000 plasma focus device, with a deuterium filling and with deuterium puffing from a gas-puff nozzle placed on the axis of the anode face. The current was reaching 2 MA. 15 interferometric frames from one shot were recorded with a Nd:YLF laser and a Mach–Zehnder interferometer, with 10–20 ns delay between the frames. As a result, the temporal and spatial distribution of the linear densities and the radial and axial velocities of the moving of plasma in the dense plasma column could be estimated.

4

Ion acceleration from intense laser-generated plasma : methods, diagnostics and possible applications

Torrisi L.

Nukleonika

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2015

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Vol. 60, No. 2

207--212

EN

Many parameters of non-equilibrium plasma generated by high intensity and fast lasers depend on the pulse intensity and the laser wavelength. In conditions favourable for the target normal sheath acceleration (TNSA) regime the ion acceleration from the rear side of the target can be enhanced by increasing the thin foil absorbance through the use of nanoparticles and nanostructures promoting the surface plasmon resonance effect. In conditions favourable for the backward plasma acceleration (BPA) regime, when thick targets are used, a special role is played by the laser focal position with respect to the target surface, a proper choice of which may result in induced self-focusing effects and non-linear acceleration enhancement. SiC detectors employed in the time-of-flight (TOF) confi guration and a Thomson parabola spectrometer permit on-line diagnostics of the ion streams emitted at high kinetic energies. The target composition and geometry, apart from the laser parameters and to the irradiation conditions, allow further control of the plasma characteristics and can be varied by using advanced targets to reach the maximum ion acceleration. Measurements using advanced targets with enhanced the laser absorption effect in thin films are presented. Applications of accelerated ions in the field of ion source, hadrontherapy and nuclear physics are discussed.

5

First dedicated observations of runaway electrons in the COMPASS tokama

Vlainić M., Mlynář J., Weinzettl V., Papřok R., Imríšek M., Ficker O., Vondráček P., Havlíček J.

Nukleonika

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2015

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Vol. 60, No. 2

249--255

EN

Runaway electrons present an important part of the present efforts in nuclear fusion research with respect to the potential damage of the in-vessel components. The COMPASS tokamak a suitable tool for the studies of runaway electrons, due to its relatively low vacuum safety constraints, high experimental flexibility and the possibility of reaching the H-mode D-shaped plasmas. In this work, results from the first experimental COMPASS campaign dedicated to runaway electrons are presented and discussed in preliminary way. In particular, the first observation of synchrotron radiation and rather interesting raw magnetic data are shown.

6

Transparent laser damage resistant nematic liquid crystal cell “LCNP3”

Raszewski Z., Piecek W., Jaroszewicz L., Dąbrowski R., Nowinowski-Kruszelnicki E., Soms L., Olifierczuk M., Kędzierski J., Morawiak P., Mazur R., Miszczyk E., Mrukiewicz M., Kowiorski K.

Opto-Electronics Review

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2014

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Vol. 22, No. 3

196-200

EN

There exists the problem in diagnostics of dense plasma (so-called Thomson diagnostics). For this purpose the plasma is illuminated by series of high energy laser pulses. The energy of each separate pulse is as large as 3 J, so it is impossible to generate a burst of such pulses by a single laser. In this situation, the pulses are generated by several independent lasers operating sequentially, and these pulses are to be directed along the same optical path. To form an optical path with ʎ = 1.064 μm and absolute value of the laser pulse energy of 3 J, a special refractive index matched twisted Nematic Liquid Crystal Cell of type LCNP3, with switching on time ƮON smaller than 3 μs was applied.

7

A new method of determining the parameters of thermonuclear plasma on the basis of multichannel polarimetric measurements

Chrzanowski J., Kravtsov Y.A.

Nukleonika

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2013

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Vol. 58, No. 2

281--285

EN

A gradient method has been proposed as an effective procedure to reconstruct real parameters of tokamak plasma by means of multichannel polarimetric measurements. High efficiency of the suggested procedure is illustrated by numerical calculations performed for a given plasma model taking into account the poloidal component of magnetic field. Polarization state of electromagnetic wave traditionally is characterized by azimuthal – ψ and ellipticity – χ angles. Evolution of these parameters along the ray is described by the equations of angular variables technique (AVT) introduced in previous works of the present authors. Numerical simulations have approved that the gradient procedure provides acceptable accuracy of inversion already after several iterations.

8

Analityka spektrochemiczna - emisyjna spektrometria atomów i cząsteczek dwuatomowych wybranych plazm bezelektrodowych

Borkowska-Burnecka J.

Prace Naukowe Wydziału Chemicznego Politechniki Wrocławskiej. Monografie

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2012

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Nr 9, nr 9

178--178

PL

Omówiono zastosowanie spektrometrii emisyjnej plazm bezelektrodowych w analizie składu pierwiastkowego różnorodnych materiałów, w analizie oscylacyjno-rotacyjnej cząsteczek oraz do wyznaczania parametrów fizykochemicznych plazmy. W pierwiastkowej analizie spektrochemicznej wykorzystano plazmę indukcyjnie sprzężoną (ICP). Badania obejmowały testowanie różnych metod wprowadzania próbek do plazmy, analizę efektów matrycowych i interferencji spektralnych w powiązaniu z diagnostyką spektroskopową wyładowania oraz opracowanie nowych, przyjaznych środowisku metod przygotowania próbek do analiz wielopierwiastkowych. Określono efektywność różnych procedur mineralizacji próbek oraz zaproponowano alternatywne nowe procedury przeprowadzenia analitu do roztworu oparte na ekstrakcji wspomaganej energią mikrofalową lub ultradźwiękową. Przedstawiono możliwość izolowania analitów od matrycy, wzbogacania analitów, obniżenia granic wykrywalności, redukcji efektów matrycowych oraz uproszczenia procedury kalibracyjnej dzięki wykorzystaniu ekstrakcji w punkcie zmętnienia. Określono wpływ różnych matryc na parametry charakteryzujące plazmę, takie jak temperatura, gęstość elektronowa, stopień jonizacji oraz zależność efektów matrycowych od parametrów fizycznych stosowanych linii analitycznych. Przedstawiono wykorzystanie bezelektrodowej plazmy chemiluminescencyjnej w badaniach struktury widm cząsteczek dwuatomowych i wyznaczaniu ich podstawowych stałych molekularnych oraz rolę i zastosowanie w analizie pierwiastkowej i diagnostyce plazmy. Stosując głównie metodę wysokorozdzielczej spektrometrii fourierowskiej, analizowano widma GeBr, PbH, PbD, Pb2 i PbLi wzbudzone w niskociśnieniowym wyładowaniu mikrofalowym oraz w reakcji chemiluminescencji połączonej z wyładowaniem mikrofalowym. Wyznaczono po raz pierwszy stałe molekularne wzbudzonych stanów elektronowych tych cząsteczek. Zaproponowano wykorzystanie widm ciężkich molekuł, takich jak Bi2 i BiN do określenia równowagi termodynamicznej w układach emitujących promieniowanie.

EN

The study demonstrates application of emission spectrometry of electrodeless plasma in analysis of elemental composition of various materials and in vibrational-rotational analysis of diatomic molecules as well as in determination of physical plasma parameters. Inductively coupled argon plasma was utilized for elemental spectrochemical analysis. Various methods of introduction of samples into the plasma, matrix effects and spectral interferences were studied in relation with physical parameters of the analytical lines and plasma characteristics. New, environmen- tal friendly methods of sample preparation for multi-elemental spectrochemical analysis have been devel- oped and verified. Various sample digestion methods were compared in terms of their effectiveness and altemative pro- cedures based on microwave or ultrasound assisted extraction have been proposed and validated. Possibil- ities of analyte isolation from complex matrix and its enrichment as well as lowering of detection limits and simplification of the calibration step were achieved by the cloud point extraction. Effects of various matrices on linę intensities and plasma parameters such as electron number density, excitation and ioniza- tion temperatures have been presented and discussed. lnvestigation of structure and determination of spectroscopic constants of diatomic molecules as well as their role and application in elemental analysis and plasma diagnostics were presented. Spectra of GeBr, PbH, PbD, Pb2 and PbLi were excited in plasma generated by microwave or chemiluminescence combined with microwave discharges. The analyses were mainly performed by the high resolution Fourier transform spectrometry. Rotational and vibrational analyses of new electronic transitions were carried out and molecular spectroscopic constants of excited electronic States have been determined for the first time. Spectra of heavy molecules such as Bi2 or BiN were proposed for plasma diagnostics and estimation of thermodynamic eąuilibrium in objects emitting radiation.

9

Preliminary determination of angular distribution of neutrons emitted from PF-1000 facility by indium activation

Jednoróg S., Szydłowski A., Scholz M., Paduch M., Bienkowska B.

Nukleonika

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2012

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Vol. 57, No. 4

563-568

EN

This paper presents a new method applied to measure the angular neutron emission from Plasma Focus (PF) - type deuterium discharges performed within the PF-1000 facility. Neutrons were recorded by activation of especially optimized (mass and shape) indium samples with subsequent gamma spectrometry to measure the induced activity of the samples. The neutron fluence rate on every indium sample used was determined using neutron transport calculation and measured activity of the samples.

10

Diagnostics of non - equilibrium plasma generated in dielectric barrier discharges

Janus H. W., Musielok J.

Nukleonika

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2012

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Vol. 57, No. 2

253-256

EN

Results of electrical and spectroscopic diagnostics of dielectric barrier discharges by applying ceramic plates made of high permittivity material are presented. The spectroscopic diagnostic is based on analysis of spectral and spatial distribution of the hydrogen H alfa emission in the gas gap. From these measurements, e.g. the distributions of electric field strength and kinetic energy of excited hydrogen atoms in the discharge volume have been determined.

11

System pomiarowy do dynamicznej spektroskopii widma emisyjnego plazmy TR-OES do diagnostyki plazmy wyładowania jarzeniowego w układzie magnetronowym zasilanym impulsowo

Wiatrowski A.

Elektronika : konstrukcje, technologie, zastosowania

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2012

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Vol. 53, nr 11

89-94

PL

Artykuł podejmuje tematykę budowy systemu pomiarowego do dynamicznej spektroskopii optycznego widma emisyjnego plazmy (ang. Time-Resolved Optical Emission Spectroscopy - TR-OES). Przedstawione rozwiązanie projektowano pod kątem zastosowania tego układu do diagnostyki plazmy wyładowania jarzeniowego wytwarzanego przez magnetronowy układ rozpylający zasilany impulsowo. W artykule omówiono zasadę działania, nakreślono podstawy konstrukcji oraz przedstawiono przykładowe wyniki zarejestrowane przy użyciu zaproponowanego rozwiązania.

EN

The article discusses the construction of measurement system for Time Resolved Optical Emission Spectroscopy (TR-OES). The described solution was designed in terms of its application for diagnostics of glow discharge plasma in a pulsed magnetron sputtering deposition system. This article discusses the principle of operation, outlines the basis of the electronic circuitry design, shows sample results obtained using the proposed solution.

12

Zastosowanie miedzi jako pierwiastka charakterystycznego przy pomiarach temperatury metodą Ornsteina

Raniszewski G., Kołaciński Z.

Przegląd Elektrotechniczny

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2009

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R. 85, nr 5

139-142

PL

Metoda Ornsteina pomiaru temperatury opiera się na pomiarze intensywności dwóch linii spektralnych. Wybrano miedź jako pierwiastek posiadający charakterystyczne, wyraźne linie w zakresie widma światła widzialnego. Celem poniższego opracowania jest określenie przydatności zastosowania miedzi przy pomiarach temperatury plazmy mineralnej.

EN

Ornstein method is based on two spectral lines intensities measurements. Copper was chosen as the element with characteristic and strong spectral lines in visible light area. The purpose of this paper is to determine usefulness of copper as a detector during mineral plasma temperature measurements.

13

Optical plasma spectroscopy as a tool for monitoring laser welding processes

Ancona A., Sibillano T., Lugara P. M. P. M.

Journal of Achievements in Materials and Manufacturing Engineering

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2008

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Vol. 31, nr 2

402-407

EN

Purpose: In this work we present experimental results of the joint application of the two previously mentioned spectroscopic techniques (electron temperature and correlation analysis) to a real-time laser welding monitoring case study. The two signals have been calculated starting from selected chemical species composing the plasma spectra. Experimental evidence is given of the correlation between the recorded signals and the occurrence of weld defects intentionally generated by varying the laser power and the travel speed. Design/methodology/approach: An optical sensor prototype was used, that embeds a fiber-coupled miniature spectrometer having a dynamic spectral range from 390 nm to 580 nm and a resolution of 0.3 nm. Such a prototype employed data acquisition and real-time spectra analysis algorithms for both the previously mentioned spectroscopic techniques, e.g. the electron temperature and the correlation coefficients. A high power CO2 laser source was used with maximum output power of 6 kW. The laser-metal interaction zone was shielded by an argon flow. The plasma optical emission was collected by a quartz collimator and transmitted to the optical sensor by a 50 μm core-diameter optical fiber. Spectral lines from three different chemical species (Mn(I), Fe(I), Cr(I)) composing the plasma plume and the stainless steel alloy were used for the acquisition of the electron temperature and the correlation signals [1]. Findings: Compared to other optical sensors, the main advantage of this system is that it has a great flexibility upon variation of the welding metal or the joint geometries. In fact once the chemical composition of the alloy was known and most plasma emission lines are identified, only a slight calibration of the software settings is necessary. Practical implications: A patented commercial version of this sensor (TRWOC from T.E.R.N.I. Research) is already available on the market. The capability of identifying the cause of the defect, once it has been detected is still limited to specific cases. Future work will regard the "intelligent" fusion of various sensor technologies aiming to increase the reliability of the system and, hopefully, realize a flexible and robust closed-loop control of the laser welding process. Originality/value: Being known the emission line parameters, this method is particularly advantageous because it does not require too many calculations and can be easily implemented in suitable software for real-time temperature measurement. Keywords: Laser welding; Plasma diagnostics; Optical sensor

14

Experimental study of a small gas-puff Z-pinch device

Luo C., Wang X., Zou X.

Nukleonika

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2006

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Vol. 51, nr 1

43-46

EN

A small gas puff Z-pinch device has been constructed and operated. The device has the parameters: the capacitance of energy storage capacitors 16 mi F, charging voltage 22 kV, peak current 210 kA and a quarter of current period 2.4 mi s. A three-frame Mach-Zehnder interferometer and a compact Thomson ion energy analyzer were developed for Z-pinch plasma experiment. According to the results of diagnostics, the electron density ne of the plasma right before pinch instant is larger than 5.4 × 1019/cm3, the corresponding pinch velocity v of the plasma sheath is 9.0 cm/ěs. Clear parabolas produced by neon ions Ne+, Ne2+, Ne3+ and Ne4+ on CR-39 target have been observed. The energy spectra dN/dTdů for Ne+, Ne2+, Ne3+ and Ne4+ ions were determined. The highest energies of Ne+, Ne2+, Ne3+ and Ne4+ ions emitted from our Z-pinch plasma are below 1.3 MeV.

15

Dynamics of the plasma plume induced during laser welding

Mościcki T., Hoffman J., Szymański Z.

Optica Applicata

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2003

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Vol. 33, nr 2-3

433-443

EN

The dynamics of the plasma plume produced during laser welding is quite complex. The keyhole wall oscillates and this results in oscillations of the plasma plume over the keyhole mouth. The metal vapour, which appears in irregular bursts, interacts with the shielding gas flowing from the opposite direction. In the present work, temporary electron densities and temperatures are determined in the peaks of plasma bursts during welding with a continuous wave CO2 laser. It has been found that during strong bursts the plasma plume over the keyhole consists of metal vapour only, without being diluted by the shielding gas. The results, together with the analysis of the colour pictures from streak camera, allow interpretation of the dynamics of the plasma plume. No apparent mixing of metal vapour and the shielding gas has been observed. In typical bursts the electron density determined from the Stark broadening of Ar I lines varies from 0.9×1023 m–3 near the metal surface to 0.5×1023 m–3 at a distance of 1.5 mm from the surface. Assuming that argon is not mixed with the metal vapour and is in local thermal equilibrium these electron densities correspond to temperatures 12.7 kK and 11.5 kK, respectively. In strong bursts the electron density varies, along the same distance, from 1.6×1023 m–3 to 0.6×1023 m–3 , which corresponds to the temperatures of 14.2 kK and 11.8 kK, respectively.

16

Laser-produced copper plasmas

Henc-Bartolic V., Kovacevic E., Kunze H.-J., Stubicar M.

Journal of Technical Physics

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2003

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Vol. 44, no 2

153-158

EN

The Cu plasmas were produced by a ruby laser (~ 5 J, 694.3 nm, ~ 18 ns, ~140 GWcm^-2). Time-resolved spectra of the plasmas were observed in the region of 8-24 nm. The electron temperature was estimated to be about 40 eV. A small depth of the crater (~ 3 [my]m) and the surrounding ripples were observed at the Cu target surface. The trace of deposited plasma was explained as the Rayleigh-Taylor instability. Plasma was transparent to the laser beam.

17

Detection of microsecond plasma pulses in MW range

Werner Z., Langer J., Stanisławski J., Białoskórski J.

Journal of Technical Physics

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2000

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Vol. 41, no 1

55-64

EN

The paper presents the preliminary results of the investigations on the detection of high power plasma pulses. Three types of detectors were examined : pyroelectric sensor, plasma-to-IR radiation converter, and thin film differential thermocouple sensor. The operation of the detectors was studied for microsecond range of the plasma pulse duration. Numerical simulation of the thermal evolution of multi-layer structures was used to optimise the design of the detectors. It is concluded that thermocouple sensors are able to provide the most relialiable data. Directions of further development of this kind of sensors are discussed.